This document contains a context help for the program RTP 4.2

Table of content

1. Common information

Introduction
Quick reference
Menu "Table"
Menu "Line"
Menu "Settings"
Menu "Calculate"
Menu "Help"
About the program

2. Operations with table

Read the table
Arrange the lines
Clear the data in the table
Print the table
Write the results
Import the data
Export for phase analysis

3. Operations with lines

Select the lines for calculation
Edit the data
Select a class for a line

4. Settings and specimen data

Specimen name
Select the emission
Select the lattice type
Select the cell centring
Correction and precision
Input the description
Options

5. Calculations

Calculated results
Calculate reflections by given hkl
Generate hkl and calculate reflections
Mark lines as a phase

6. Indexing

Indexing by shuffle or by known hkl
Indexing is in progress
Current result of indexing
Indexing is completed

7. Errors and troubleshooting

No information about lattice type
File format error
Insufficient data for calculation
Wavelength is changed
Lack of independent lines
Too many h k l combinations
Table size overflow
First approximation is failed
No other lines except basic are found
Misconvergence

1. Common information

Introduction

Tabular processor for X-ray diffractometry helps
with common calculations in the practice of X-ray
structure analysis: calculate the lattice parame-
ters (constants), estimate the quality of results,
search the indices of reflections from unknown
structures, calculate the reflection grid for
known lattice, check the goniometer alignment.

Most functions are accessible via main menu (F10).
The context help (F1) and general help (Shift+F1)
are available any time. Please also note the tips
on the screen bottom.

             Technical characteristics
Calculated lattice types: from cubic to triclinic.
Calculated data: lattice constants, cell volume;
c/a relation for hexagonal, tetragonal and ortho-
rhombic lattices; orthorhombic splitting.
Limits by indices h k l        : from 0 to 99
Limits by interplanar distances: 0.02...99 A
Limits by lattice edges a, b, c: 1...99 A
Limits by lattice angles       : 1...179 degrees
Precision of edge calculating  : 0.00001 A
Maximum table size             : 200 lines
Number of labelled phases      : 5

                   Other options
- Calculation the lines position with generation
  of h k l by given parameters and lattice type.
- Calculation the lines position by given parame-
  ters and indices h k l, listed in the table.
- Indexing with shuffle or by known h k l methods
  for lattices from cubic up to monoclinic.
- Read PDF cards which are written in *.aid format
  by PCPDFWIN program (from PDF-2 software kit).
- Import 2th or d, intensity and indices from text
  files (for example, from Excel in *.txt format).
- Export 2th and intensity table in ASCII format
  compatible to phase analysis programs.

                System requirements
Win32 version: Windows 2000/XP/Vista/7
Recommended settings for Windows console:
Screen buffer size - 80x25 (supported up to 80x50)
Font - Lucida Console 16...20; raster 8x12, 10x18

Quick reference

                 Program functions
F1    - context help; index in help window
F2    - open a file
F3    - arrange the lines the table
F4    - select the emission (wavelength)
F5    - set the lattice type (syngony)
F6    - calculate the lattice parameters
F7    - set the Bravais cell
F8    - clear the table
F9    - print the table
F10   - enter the main menu
F11   - mark the calculated lines as a phase
F12   - exit the program, also Alt+X
Esc   - cancel; stop of auto re-calculation
Alt+W - write results to a file *.par
Alt+R - write results to a new file
Alt+M - import a data list from *.txt file
Alt+P - export table to *.txt for phase analysis
Alt+N - input the specimen name
Alt+E - input 2th correction and precision
Alt+D - input the specimen description
Alt+O - view or change the program options
Alt+A - calculate angles by known hkl
Alt+G - generate hkl and calculate reflections
Alt+I - indexing the reflections in the table
Shift+F1 - quick reference (this screen)

               Operations with lines
Enter - input or edit data in the current line
^C    - copy line to a buffer
^V    - paste line from buffer in current place
^X    - delete line and copy data to a buffer
^N    - insert a new empty line
Space - select/unselect the current line
^L    - select lines with calculated 2th values
^A    - select all lines which possible
^I    - invert selection of all lines
Shift+Up
Shift+Dn - select/unselect sequence of lines
Ins   - set a class for current line

             Editing data in the table
Enter - input value, go to next cell or line
Esc   - restore value in the cell, exit edit mode
Tab   - go to next cell
Shift+Tab - go to previous cell

             Estimation of the results
    (rms - root mean square, dev. - deviation,
      prec. - precision of 2th, i.e. +-2th)

   excellent:     dev. < prec. for all lines
   very well: rms dev. < rms prec.
        well: rms dev. < rms prec. * 2.0
satisfactory: rms dev. < rms prec. * 4.0
        poor: rms dev. > rms prec. * 4.0

quality degrades:
 by 1, if lines number < parameters number * 2
 by 2, if lines number = parameters number + 1
not defined, if lines number = parameters number

Menu "Table"

This menu includes the operations with the table.

Open      - read the data file *.par or *.aid
Arrange   - re-organise the lines in the table
Clear     - remove a part or all data in the table
Print     - output table and results to printer
Write     - save table and results to file *.par
Write as  - save table and results to a new file
Import    - import a data list from *.txt file
Export    - save table for phase analysis, *.txt
File list - read one of last files (up to 5)
Exit      - exit the program, also use F12

Menu "Line"

This menu includes the operations with lines;
convenient keyboard shortcuts are also available.

Edit        - input data or edit the fields in the
              current line
Cut         - delete current line, store its data
              in the buffer
Copy        - copy current line to the buffer
Paste       - restore line from the buffer
New         - add a blank line at current position
Select      - select/unselect line for calculation
Select calc - select all lines with calculated 2th
Select all  - select all lines with valid data
Invert all  - invert selection of all valid lines
Set class   - select a phase or class for a line

Menu "Settings"

This menu allows to set different specimen-related
data and conditions of diffractometry.

Specimen name - input the specimen name, 16 chars
Wavelength    - select the emission from the list
                or input the wavelength manually
Lattice type  - set the syngony (or Bravais type)
                for specimen or current phase
Bravais cell  - set the Bravais cell centring
Correction    - set angles of standard substance
                for correction; set 2th precision
Description   - write or view a short note about
                the specimen or calculated phases
Options       - view or change the configuration
                of the program (also in rtp.ini)

Menu "Calculate"

This menu allows to calculate the lattice parame-
ters, diffraction angles and use the indexing.

Parameters    - calculate lattice parameters by
                selected lines of current phase
Angles by hkl - calculate reflection angles by
                parameters for hkl in the table
Generate hkl  - calculate reflections by given
                parameters and Bravais cell
Indexing      - find possible indices for lines
                using lattice type and cell
Mark lines as - mark lines as belonging to a phase

Menu "Help"

This menu allows to get the information about the
program. To show the table of content, press F1 in
the help window or click "i" (index) with mouse.

Context - help on current program mode or status
General - quick reference about keyboard commands
          and estimation of the results
About   - current program version and developers

About the program

Thank you for using the program RTP, and good luck
in the researches using X-ray diffraction method!
Any opinions about the program, information about
possible problems, issues as well as other useful
suggestions will be received with gratitude.

Basic ideas and some code used in the program were
developed in late 80's by staff of X-ray research
laboratory of the Institute of Inorganic Materials
in Moscow: Andrey V. Golubev, Michael A. Poddyakov,
Konstantin I. Avertsev, Yaroslav N. Chebotarev.

                   Contributions
K. Avertsev - ideas and algorithm of the shuffle
method used for indexing.
A. Golubev - ideas and algorithm of generation of
indices for different lattices and Bravais cells.
M. Poddyakov - first version of RTP, basic code of
solving the matrix using the Gauss method, calcu-
lation of lattice parameters up to monoclinic.
Ya. Chebotarev - calculation of triclinic lattice,
2th correction, user interface, help system, Win32
version of program. Contacts: http://slavic.pp.ru

_ _ _ _ _ _ _ _ _ _

2. Operations with table

Read the table

Select a data file from list (change the directory
or drive if necessary). Usually here are shown the
files *.par, created with this program, and *.aid,
which were exported from PCPDFWIN.

                   Control keys
Tab, Shift+Tab - select list, file mask or disk
^D  - arrange file list by name (in ascending)
      or by date (in descending)
^R  - re-read the file list
Del - delete current file

                Control with mouse
Left click   - set the marker at cursor position
Double click - select a file to read
Wheel        - scroll the marker

Network storages can be mapped to logical drives;
a path also can be entered manually in UNC format:
press F2 in the file mask field.

Arrange the lines

You can arrange the lines in different ways:
- by increase 2th: allows to arrange the lines by
  ascending of their 2th and descending of d;
- by decrease 2th: allows to arrange the lines by
  descending of their 2th and ascending of d;
- by phases: allows to arrange the lines by known
  phases: numbers (N), then phases (1), (2) etc.,
  then standard substance (s), common (c) and
  excluded (x) lines. Within any phase, the lines
  will be arranged by ascending of 2th;
- by deviations: allows to arrange the lines by
  descending of absolute values of deviations.

Clear the data in the table

First option clears the entire table. If you sup-
pose to use this table later, write it to a file.
Other options allows:
- clear the table and keep the lattice parameters,
if you wish to generate the reflections grid;
- clear the indices h k l, if you decide to input
them manually instead of current values;
- clear the data (2th, d, and I), if you wish to
apply the existing indices to other substance
(e.g. you may import the card from PDF database as
the structure prototype and use its indices);
- clear the last calculated results, if you decide
to calculate them again with different settings;
- clear all basic marks from lines in the table to
select other set of basic lines for indexing;
- clear the phases to remove all phase labels and
numerate lines in ascending. The information about
structure of all phases except (N) will be lost.

You do not need to clear all table to calculate
another sample with the same structure: input new
2th or d values and select the lines.

Print the table

Confirm output the table and calculated results to
the printer. Standard printer port is lpt1, it can
be changed in Settings -> Options. You can also
switch on/off the automatic format feed, see the
parameter "printff" in rtp.ini configuration file.
Before printing, make sure that printer is online.

(In Windows XP, to use a network printer with DOS
version of RTP, this printer should be mapped to
local port lpt1 using the console command like:
net use lpt1 \\machine\printer /persistent:yes
This is not required for Win32 version of RTP.)

Write the results

To save results on disk, input the file name; the
extension is recommended to leave as is. Use Tab
or Shift+Tab combination to switch between file
list, file name and disk selection fields. You can
also select any file and use its name as a pattern
or overwrite it.

Import the data

You can import the list of 2th or d and some ad-
ditional data, prepared in ASCII *.txt format.
This list may include the header with the specimen
name and wavelength beginning from ";" (optional),
then the lines with 2th or d values (required),
intensity (optional) and indices h k l (optional):
; Nickel FCC
; 1.54051
44.51  100  1 1 1
51.85   40  2 0 0
76.37   20  2 2 0

This format is corresponding to data format of PDF
cards. RTP attempts to determine by a first value
(more or less than 10.0) whether it is related to
2th or d. You should check and confirm the choice.
If the line with wavelength has not been included,
you need to set it manually after the import.

Export for phase analysis

You can export the table in ASCII *.txt format and
use it for phase analysis. This table contains the
header with specimen name and wavelength and then
the data lines with 2th and I values (if no any
intensities are known, 100 will be set instead):
; Nickel FCC
; 1.540510
 44.5100    100
 51.8500    40
 76.3700    20
Use an option "Import ASCII" in the phase analysis
program to import the table.

Exit the program

Check whether the table and the calculated results
have been written to a disk, if necessary.

File operation error

The file or directory is not found or cannot be
opened. Most likely you made a mistake typing the
name. Another possible reason: you deleted a file
which name was stored in the recent list; this
file will be removed from the list automatically.
More rarely you may see this error because you do
not have an access to the external device or lack
of required permissions.

_ _ _ _ _ _ _ _ _ _

3. Operations with lines

Select the lines for calculation

The selected lines of each phase are marked with
blue background (or green under marker) at least
until "I" column. You cannot select the lines with
errors or incomplete data; they will be grey on
white background until correction.

If some indices h k l are marked with yellow, they
are not match with current lattice type or Bravais
cell, but such lines will be calculated anyway.

                   Control keys
Space    - select/unselect line for calculation
Shift+Up,
Shift+Dn - select/unselect sequence of lines
Enter    - edit a cell in current line
^C       - copy current line to a buffer
^V       - paste line and data before current line
^X       - delete current line
^N       - insert a new line before current one
Ins      - set or change a class of current line
B        - set/cancel basic line for indexing
See keys for editing data in help for menu "Line".

                Control with mouse
Left click  - set the marker at cursor position;
            - call the class menu in "#" column;
            - edit the cells in columns "h k l" to
              "I" in the current line;
            - select/unselect current line for
              calculation in two right columns
Right click - select/unselect current line;
            - cancel editing data in the cell
Wheel       - scroll the marker

         Calculate the lattice parameters
To calculate the lattice, its lines must have non-
empty h k l and valid 2th. In indexing mode, lines
must have at least valid 2th and precision +-2th.

Use F6 to calculate lattice parameters by selected
lines of current phase. If the table contains more
than one phase, the current phase is defined by
current position of the marker. To calculate an-
other phase, set the marker on any line of that
phase and press F6 again.

Before the first calculation please make sure that
you have set the correct lattice type (F5) of cur-
rent phase.

Edit the data

To calculate the lattice parameters, fill in the
fields: h k l, 2th and +-2th or d and +-d. Lines,
that are suitable for calculation, are marked with
blue background. For indexing, the indices may be
skipped; the intensity values may be very helpful.

                   Control keys
Enter - input a value, go to the next cell/line
Esc   - restore value in the cell, exit edit mode
Tab   - go to next cell
Shift+Tab - go to previous cell
Shift+Right,
Shift+Left - select characters in the cell
^C    - copy selection to a buffer
^V    - paste selection in current place
^X    - delete selection and copy it to a buffer

                Control with mouse
Left click   - edit a cell in the current line
Right click  - cancel editing and restore a value
Double click - input a value, go to the next cell
Wheel        - scroll the marker

Select a class for a line

Here you can choose a class for current line:
1...4 - one of specified phases (groups of lines);
S     - a line of the standard substance;
C     - a line, common for several phases;
X     - a line, excluded from all groups.

You can also clear all line assignments (N). For
indexing, the line can be marked as basic (B); to
cancel this mark, use the same option.

Please note: all these marks can be set immedia-
tely without the menu using the highlighted keys.

_ _ _ _ _ _ _ _ _ _

4. Settings and specimen data

Specimen name

Input or edit the specimen name (max. length is 16
characters). If you want to store more information
about specimen, such as element or phase compound,
structure and other details, use the description
window (Alt+D).

Input the emission

Input the wavelength for current experimental data
(in Angstroems). This value will be stored for
next use in the file rtp.ini, parameter "wave".

Select the emission

Select the emission type or wavelength from the
list of emissions, which are widespread in the
X-ray analysis. You can also input the wavelength
manually. The last used value is stored in the
configuration file rtp.ini, parameter "wave".

The internal table of wavelengths (which are more
traditional than physically true) can be replaced
with data from the file rtpwl.ini, it should be
placed in the program's directory. This file can
contain up to 18 data lines, each includes the
name, wavelength and short description. Example:

; Name  Lambda   Description
&Cu-Ka1 1.540593 Emission of copper, line K-alpha1
Cu-K&b  1.392235 Emission of copper, line K-beta

Select the lattice type

Select the Bravais lattice type (syngony) for in-
vestigated crystal substance or phase.

If the table contains more than one phase, the
current phase is defined by current position of
the marker.

Select the lattice type

Select the supposed Bravais lattice type (syngony)
for investigated substance of phase. If a syngony
is unknown, it is recommended to begin the index-
ing process from the types with higher symmetry.

Select the cell centring

Select the Bravais cell centring for current lat-
tice type. Indices, which do not correlate to cho-
sen centring, are marked in the table with yellow.
Use option "find highest" to find higher centring.
In the indexing mode this setting allows to choose
the most centred cells over the less symmetric
ones, even when they give more described lines.
The unrealisable centrings are marked with grey.

Note: rhombohedral centring is realisable in the
hexagonal lattice; the cell type of the rhombohed-
ral lattice itself is always primitive.

Select a line belonging to a phase

You need to point at one of the lines belonging to
a known phase which you would like to calculate or
define. Empty, common and excluded lines cannot be
used for this. Please move the marker accordingly.

Options

Here you can view and change some settings which
are stored in the rtp.ini configuration file.

File mask for reading: *.par;*.aid
This mask is used in file window, by default it
shows the files *.par created by this program and
files *.aid, exported from PDF-2. You may set *.*

Default PDF-2 precision: 0.010
The cards exported from PDF-2 database may not
contain any information about 2th precision; in
such case this value will be used instead.

Indexing delta multiplier: 4.0
This value is a multiplier for experimental preci-
sions of 2th, which defines a window for search
for adjacent reflections in indexing mode. In some
cases a value from 3 to 5 may be reasonable, but
generally, if you have the problems with indexing,
try to change 2th precision first.

Radius of detector circle: 200
A distance between specimen and first slit of de-
tector, in millimetres. It allows to calculate the
exact value of specimen displacement by 2 or more
experimental angles of standard substance. Besides
displacement, it does not affect any results.

d of standard substance #:
You may input from 1 to 5 interplanar distances of
external standard, used for calculation of correc-
tion. Angles are calculated at current wavelength.
To restore default data, input 0 in all 5 fields.
Default data: natural diamond at 25C, a=3.566986
(Hom T et al, J. App. Cryst. 8 (1975) pp.457-458)
 h k l      d
 1 1 1   2.059400
 2 2 0   1.261120
 3 1 1   1.075487
 3 3 1   0.818323

Printer port: lpt1
Instead of standard port lpt1 you may input the
name of a port, which a local printer is connected
to, or a network port like \\machine\printer

Correction and precision

To correct the experimental angles, you can either
use the experimental angles of standard substance
or input the parameters of correction manually.

If you use standard substance correction, input in
the right column from 1 to 5 experimental angles
(left column is for theoretic angles, see below).
Single angle gives the constant correction; two or
more allow to calculate the specimen displacement.
If the table contains some standard lines, you can
input their numbers with "#", e.g. #4. You may in-
put "#" without number, then the nearest line will
be used. Leave 0 values in empty fields.

Alternatively, you can input the constant correc-
tion and specimen displacement manually.

You can change 2th precision for all lines in the
table, this affects the results estimation and in-
dexing. For pattern line, use "#" and line number.
To apply default value, press Enter in this field.

Finally, use "Apply" to correct the angles of all
lines in the table and/or change their precision.

Field "Inverse" allows to make the inverted cor-
rection (and change a precision as well). This is
useful when you need to compare the lines, calcu-
lated from lattice parameters or imported from
PDF card, with experimental data.

                 Technical details
Formula used:
correction=constant-2*cos(th)*displacement/radius

Constant (zero-point) correction should be added
to all experimental angles to compensate the shift
of detector from ideal position. Specimen displa-
cement gives the correction depending on cos(th).
A positive value means the shift of specimen plane
toward the diffraction angle, negative - backward.
Both these parameters are obtained using the least
squares method from cosine - divergence data set.
Calculation of displacement also uses the detector
radius stored in rtp.ini (typical value is 200mm).

Theoretic angles are calculated from interplanar
distances, which are stored in rtp.ini, at current
wavelength. Use Settings -> Options to see/change
these data.

Input the description

You can input the short description of specimen or
its phases, if they are specified. Any string may
have up to 60 characters or be empty. Non-empty
strings will be written at the end of file *.par.
When you read a file *.aid from PCPDFWIN, first
two strings are filled in automatically.

Correct angles in the table

Two parameters defining the angle correction: con-
stant and specimen displacement were calculated.
Now to get the true position of all reflections,
they should be applied to whole table. You can
cancel this operation and input the standard ang-
les again.

_ _ _ _ _ _ _ _ _ _

5. Calculations

Calculated results

The top window shows the results of lattice calcu-
lation: the parameters and cell volume. For some
lattices the relation c/a is also calculated, and
for orthorhombic lattice - split rate (b-a)/(b+a).
Error 1 is an effect of the limited 2th precision;
error 2 is defined by deviation of the experimen-
tal angles from the calculated ones. Deviation is
a value which has to be added to calculated angle
to obtain the experimental data.

The quality of results is estimated by relation of
2th root mean square deviation to mean experimen-
tal precision. The lines where a deviation is more
than precision * 4 are marked with yellow.

Two numbers separated by slash on the left from
estimation show the number of lines used in calcu-
lation and total number of lines of current phase.
Its background shows the re-calculation mode: cyan
if active, white if not. To cancel the automatic
re-calculation, press Esc or left-click on the
numbers with mouse.

              Control with keys/mouse
Space       - select/unselect line for calculation
Shift+Up,
Shift+Dn    - select/unselect sequence of lines
Ins         - set or change class of current line
Left click  - set the marker at cursor position;
            - call the class menu in "#" column;
            - select/unselect in two right columns
Right click - select/unselect current line

                 Technical details
The main algorithm is based on the method of least
squares. The system of linear equations is obtai-
ned from original data using a classic Bragg law. 
The resulting matrix with dimension equal to para-
meters number of current lattice is solving using
the Gauss method. The errors, which are due to 2th
precision (Errors 1), are obtained from the solu-
tion of this matrix. The errors due to divergence
between the calculated model and the original data
(Errors 2) are obtained by solving another matrix
which is composed by deviations between calculated
and original 2th.

The 2th angles are calculated from lattice parame-
ters using the standard equation for interplanar
distances (1/d^2) for current lattice types.

Calculate reflections by given hkl

For calculation the reflection angles by given in-
dices and parameters, the data in column "h k l"
must be filled in. Change the lattice type (F5),
if need. Then fill in the lattice constants.

Moving between the fields: Up, Dn, Tab, Shift+Tab.
Limits for edges a, b, c - 1...99 Angstroems, for
angles alpha, beta and gamma - 1...179 degrees.

Generate hkl and calculate reflections

To calculate the reflections with generation indi-
ces hkl select the lattice type (F5) and set the
Bravais cell, if it is known, or leave the type
"primitive". Then fill in the lattice constants
and set the minimum and maximum values of 2th.

Moving between the fields: Up, Dn, Tab, Shift+Tab.
Limits for edges a, b, c - 1...99 Angstroems, for
angles alpha, beta and gamma - 1...179 degrees, 
for angles 2th - 0...179 degrees.

Mark lines as a phase

You can mark the lines that have been used in cal-
culation of lattice parameters as a separate phase
or a group by a certain number from 1 to 4. These
lines will be labelled in the left column of the
table by the number in parentheses: (1) to (4).

To remove the phase marks and restore the ordinal
numeration of a group of lines, choose an option
"Numbers" (N) for this group (you can also mark
any individual line using the "Ins" menu).

_ _ _ _ _ _ _ _ _ _

6. Indexing

Indexing by shuffle or by known hkl

Shuffle method uses the generated array of h k l,
which are sequentially assigned to basic lines to
get the lattice parameters; a reflection grid is
calculated and checked for coincidences until the
threshold reached. You can mark "*" basic lines
manually or they will be taken from top of table.

Method by known hkl assumes that indices of basic
lines are known; only one reflection grid is cal-
culated and checked. Basic lines with h k l are
required, only limits by indices are used.

Limits by h k l: 5 5 5
The higher limits increase the chance of success,
even with non-minimal cell, but increase amount of
cycles and time. A size of h k l array in RTP32 is
4096. For a primitive Bravais cell and for cubic
lattice h k l must not exceed (46 46 46) with mul-
tiplicities, for orthorhombic lattice - (15 15 15)
and for monoclinic one - (12 12 12). If a cell is
non-primitive, limits can be increased.

Limits by a b c: 10 10 10
Set a maximum size of lattice. You can input less
than 3 values (e.g. for cubic lattice). Higher
values increase a chance to find the non-minimal
cells. Possible limits 1...99.

Limit by V: 1000
Volume can reduce the amount of non-minimal cells.
To calculate the volume from given a b c, input =
in this field, press Enter.

Threshold in %: 80 (x/n)
Minimal percent of indexed lines. Recommended
value 70...90, possible limits 25...100.

Lattice type and Bravais cell
Supposed cell of lattice (see context help for
these fields).

                 Technical details
In a shuffle cycle, the basic lines get the cur-
rent combination of indices from h k l array, lat-
tice parameters are calculated and checked against
given limits by a b c and V. A grid of reflection
angles is built from the h k l array and used to
search for the reflections adjacent to experimen-
tal angles within the delta * precision area (see
Settings -> Options). Indices of reflections may
be checked for Bravais cell with higher symmetry
(it is limited by basic lines). If amount of lines
is high enough, the results will be shown.

Indexing is in progress

In the bottom line of the screen you can see cur-
rent information about indexing: size of hkl array
and current indices for basic lines, except last
one. The shuffling of h k l is proceeded in ascen-
ding the sum of their squares.
If the parameters calculated for basic lines cor-
respond to the initial indexing settings, they are
shown on the screen, and the described lines are
marked with blue. You can interrupt the indexing
or change the indices of first basic line to the
next generated combination (Esc).

Current result of indexing

Please verify the indexing results: look at per-
cent of described lines and a cell volume, check
the validity of lattice parameters. If you suppose
that results are reliable, it may be helpful to
write them under a separate name (Alt+R) or print
this table (F9).

Press Esc to see or hide the control menu.

You can continue the indexing process or decide to
change the indices of first basic line to next hkl
combination. Also you can exit the indexing cycle.

Indexing is completed

Indexing process is finished, when the indices of
1st basic line reach the maximum h k l values. If
the intermediate results were written to disk or
printed, choose the more suitable of them. Other-
wise, it is recommended to repeat the indexing
process and select the most reliable results.

If the initial settings were unsuited (incorrect
basic reflections were selected, threshold is too
high, limits by h k l or lattice constants are too
small, incorrect lattice or cell is selected), the
results will be probably unreliable. Try to change
some initial settings and repeat the indexing.

_ _ _ _ _ _ _ _ _ _

7. Errors and troubleshooting

No information about lattice type

This message means that a file does not contain an
information about lattice type of the substance.
This may be because you opened a very old PDF data
card or obsolete file of early RTP versions.
Hence, you cannot calculate lattice parameters.

Cubic type is assigned as assumption. In fact, you
have to set the real type instead if it is known;
otherwise try to assign the different types or use
the indexing procedure.

No indexing for triclinic lattice

Indexing for triclinic lattice is not supported in
program RTP because it requires the implementation 
of special algorithms; shuffle method is ineffici-
ent in this case. Please try to use other specia-
lised software.

File format error

The file cannot be opened because it is either da-
maged or its format is not supported by current
version of the program. Please check whether the
file has the format *.par, *.aid, or the format
*.txt, suitable for data import.

Although the files *.par have the conventional
text format and can be inserted in reports, used
for printing etc., you should be very careful with
editing them manually, because some fields, which
are critically important for proper recognition of
the data, have the fixed positions. It is highly
recommended to make any changes of the data inside
the RTP, not in external editors like Notepad etc.

Insufficient data for calculation

The minimal amount of lines, which are selected
for calculation, must not be less than number of
lattice parameters in given syngony; for statisti-
cal reliability this amount has to be more than
minimal. Try to select some additional lines.

Indexing requires at least the number of lattice
parameters plus 1 line.

In indexing mode by lines with known h k l, the
amount of lines, marked by asterisk as basic, has
to be equal to the number of parameters.

Wavelength is changed

You might have skipped setting the correct wave-
length before filling in the table, but decided to
do this now. So, you need to select a way to cor-
rect the data in the table. If the 2th angles are
true, need to re-calculate all interplanar distan-
ces; otherwise, if the existing distances d are
the primary data, need to re-calculate the angles.
You may also cancel the change and return to the
previous wavelength.

Indexing is interrupted

You can continue the indexing or use other options
- change the indices for 1st basic line or exit.
"Next" assigns the next hkl values from generated
array to this line.

The reasons to exit the cycle: the absence of any
results for a long time, or when results are unsa-
tisfactory because of unsuitable initial settings.
Please note that for complex lattices (orthorhom-
bic and especially monoclinic) the full shuffling
cycle of indices array requires a lot of time.

Lack of independent lines

The quantity of lines that contain linearly-inde-
pendent indices is less than minimal quantity re-
quired for calculation. Most often this may occur
at calculation of low-symmetric lattices.

Try to select for calculation some other lines
instead of current ones or increase the amount of
selected lines.

Too many h k l combinations

The number of possible h k l combinations is limi-
ted by 4096 in current Win32 version of RTP.
If Bravais cell is primitive, use the estimations:
for cubic lattice h k l must not exceed (46 46 46)
(with multiplicities), for orthorhombic lattice -
(15 15 15), and for monoclinic one (12 12 12). If
a cell is non-primitive, limits can be increased.
(In a DOS version the number of h k l combinations
was limited to 1024 and the values mentioned above
might be (23 23 23), (9 9 9) and (7 7 7).)

Decrease one or more maximum values by h, k or l,
until the overflow disappears.

Table size overflow

The number of possible hkl combinations for given
2th range exceeds the table size (200 lines), and
the program has automatically decreased the upper
2th limit. As a result, some of possible reflecti-
ons will not be included. See the last calculated
angle at the end of the table.

First approximation is failed

There is no convergence at the attempt to calcula-
te the lattice parameters from selected basic li-
nes - the indices of these lines are probably li-
nearly-dependent. Try to select some other basic
lines with known indices or try to use the shuffle
indexing method.

No other lines except basic are found

The lattice parameters have been calculated at the
first approximation by the lines with known h k l,
but an attempt to find the indices for other lines
was failed. Probably, the real fallibilities of
most other reflections are greater than the preci-
sions shown in the table. Try to increase +-2th or
select other lines with known indices as basic.

Misconvergence

This message means that calculated results do not
have a physical sense, e.g. negative values were
obtained. Most probably it may be because of error
in some lines, like wrong indices or angles.

Thoroughly check all data in the table. Also try
to unselect some lines and select other ones until
this error disappears.

Another cause of this error: the number of linear-
ly-independent indices is less than number of lat-
tice parameters. Add more lines for calculation.

_ _ _ _ _ _ _ _ _ _