**[View_Spw** | **Energy
**| **Fields** | **FAIW** | **Params** |
**Coseul | Help]**

It is a program for preliminary treatment of EPR, ENDOR and other spectra.

The program allows:

1. To browse all spectra in directory (or, selectively, EPR or ENDOR only),- it helps you
in few second to find the spectrum, what you need;

2. To convert the spectrum from one format to another - the program recognizes
several different
formats:2 binary formats - byte (BRUKER) and single (WIN-EPR), 2 ASCII formats - one
column (Y) format with signal intensities only and two column (X and Y) format with
sweeping parameter values and intensities (the last are usually used in graphical
programs, like “ORIGIN”, “GRAPHER”,...) ,
as well as *.sta, *.fls and *.jdx -formats;

3. To view a spectrum with “ZOOM” along X or Y or both directions;

4. To estimate line positions (g-factor, resonance magnetic field or frequency) and
distance (splitting) between any points in the spectrum;

5. To carry out filtering of the spectrum with the help of one of 9 filters with variable
width: movement, Gaussian, Lorentzian, polynomial, Fourier and other filters;

6. To carry out automatical or manual peak-peaking of the spectrum - efficient
auto-peaking procedure recognizes both absorption and derivative shapes of resonance
lines; manual peaking procedure allows you to add unresolved peaks on the screen and into
data file;

7. To estimate effective g-factor value of any line;

8. To compare several spectra on one screen;to carry out algebraic transformations of 2
spectra: C = A + k*B or C = A - k*B;

9. To print 1-8 spectra on the page together with the spectrum parameters;

10. To prepare a file with parameters of your spectra (polar and azimutal angles of
magnetic field direction, temperature, microwave frequency and so on);

11. To collect all parameters of all spectra in the directory in one file ( for data
base);

12. To prepare the file with angular dependencies of the spectra, i.e. to collect the
positions and intensities of resonance lines (from all peak-files) and the values of polar
and azimutal angles (from corresponding parameter files) and automatically sort them. You
can view and treat these angular dependencies with the help of FAIW
program.

A special procedure allows to decompose complex spectra consisting of overlapping lines
into separate lines with definite shapes (Gaussian, Lorentzian, triangular pedestal, their
first derivatives, multiplet of up to 40 such lines, and also with any line shape, given
by the user as a table).

No one of other known programs does grant you most of these posibilities.

**ENERGY** -
is a part of Fields.exe program, which allows to obtain the
following dependencies:

1. Positions of energy levels on magnetic field;

2. Differencies of energy levels on magnetic field;

3. Transition intensities on magnetic field;

4. Electron Paramagnetic Resonance (EPR) spectrum shape

on line width and line shape (Gaussian, Lorentzian and their derivatives),

on azimutal or polar angles,

on any parameter of spin-Hamiltonian,

on random distribution of any parameter of spin-Hamiltonian,

on microwave frequency,

on temperature.

The program imitates a sweep of the static magnetic field from Bmin to Bmax and calculates the position of resonance lines by linear interpolation of energy level dependencies on magnetic field.

**FIELDS** - calculates the
angular dependencies of resonance magnetic fields and intensities of EPR lines for the
rotation of magnetic field in any plane. The program imitates a sweep of the static
magnetic field from Bmin to Bmax. Near resonance it uses a small field steps with cubic
interpolation of energy level dependencies on magnetic field; far from resonance it
increases this step. This algorithm is much faster than step by step sweep as in ENERGY.

There is a special spreadshhet for creating of <*.gep> file with all necessary parameters for work of FIELDS/ENERGY programs: the parameters of Zeeman B*S and B*S*S*S interactions, the parameters of crystalline field and hyperfine S*I interactions in the Spin-Hamiltonian, microwave frequency, Euler angles for equivalent centers (if present), spins of particles, initial and final orientations of the static magnetic field relative to the coordinate system, which is characterized by polar and azimuthal angles, steps on angles and some others. If such file exists and open, you can edit it.

**FAIW** This is powerful tool for viewing, comparing and transformation of
2-3-4 dimensional arrays of EPR, ENDOR or other data..

It visualisates experimental or calculated angular dependencies of resonance
magnetic fields (EPR) or resonance frequencies (ENDOR) and convert into special symbols
the information about other resonance line characteristics - intensity and width.

It permits also to extract the points, what you need, from array of experimental data and
to prepare the data for fitting with the help of PARAMS or ENDOR.

It works with special <*.grt> or <*.grm> ASCII files. These files are output
files of View_Spw (experimental angular dependencies) or Energy, Fields (calculated angular dependencies).

**PARAM(eter)S** permits to obtain parameters of
Spin-Hamiltonian by fitting of calculated and experimental angular dependencies of EPR
spectra. The program minimizes divergence between calculated and experimental values of
the resonant magnetic fields with the help of variation of Spin-Hamiltonian parameters. It
uses nonlinear methods of minimum search.

Input data: resonant magnetic fields at some orientations (polar and azimuthal angles) of
constant magnetic field relative to crystal coordinate system; common microwave frequency
or own microwave frequencies for each resonance line, Euler angles for equivalent centers
(if present), spins of particles, the information about what terms of the Spin-Hamiltonian
must be taken into account.

**CosEul**(er) allows you:

1. To get the values of Euler angles for any coordinate system. If A, B, C - orthogonal
axes of this system, you can input 3+3 components of its B and C vectors in XYZ coordinate
system, the program calculate third vector A and Euler angles of ABC relatively XYZ.

2. To transform principal vector or tensor components from initial coordinate system to
any other one, rotated relatively initial on Euler angles Alpha, Beta, Gamma.

3. To receive principal values of symmetric second rank tensor and 9 cosinuses of
principal axes and Euler angles of principal coordinate system relatively initial one.
Cartesian or irreducible components of the tensor can be used.

4. To transform irreducible components of symmetric second rank tensor to Cartesian ones
and back.

There
are general tutorial "Visual EPR. Basics" and tutorials for every program of the **Visual EPR**
package.

Revised: June 05, 2013.