A Computer Program for Slmulatlng Single Crystal Electron Spln Resonance Spectra A computer p m g r m has been written in Fortran N for simulating single crystal electron spin resonance spectra to first order. Execution ofthe program requires approximately 30K on a CDC 3300 computer (90K of 24-bit words) and the execution time is between 20 see and 5 min, depending upon the complexity of the spectra and the number of calculations in one run. The program simulatw the esr spectrum associated m a given orientation of the crystal in the external magnetic field from a number of radicals simultaneously present, earh of them being characterized by an unpaired electron interacting with several different or equal nuder. The resolution of the simulated spectra io 125 mC at a +SO C. scan width. Other feature3 of the program are: The spectra may be presented as normalized Lorenzian or Gaussian absorption curves,or as the f i n t or semnd derivatives thereof. Each radical contributing to the totalspectrum may be given different peak-to-peak line widths as well as different relative intensities to allow for concentration differences between the contributing radicals. It is possible to make systematicvariations of the crystal in the magnetic field, of the line widthsand of the relatik intensities. The last ootion facilitates simulation of soectral behavior to uv-bleaehine or temoerature annealine of the crvstal. The input to the program misists mainly of the principal valu& of themagnetic interactions tog&& with their direction cosines related to an orthogonal coordinate system fixed to the crystal. The desired orientation is defined by the polar angles to the external magnetic field in this reference frame. Additional data inputs are required far the line shapes, line widths, relative intensities and the plotting routine. An exhaustive set of comment cards are included describing the data inputs and their formats. Output from the program consists of a plot (with adjustable width and height) of the spectrum (CalComp digital plotter Model 565) andlor a numerical listine- of several soeetral data as well as the relative line intensities as a function of a gauss scale. On request a copy of the listing of the program will be supplied free of charge. Card decks or magnetic tape listings will not be supplied.
Institute of Physics University of Oslo Blindern, Oslo 3, Norway
Einar Sagstuen
Volume 54, Number 3, March 1977 1 153
