spectrum.c takes vibrational frequencies and intensities and plots a realistic-looking spectrum. It is written in strict ANSI C and should compile painlessly with cc spectrum.c -o spectrum -lm =========================================================================== ------------------------------------------------------------------ Paul Soper All the usual disclaimers apply DuPont Central Research soperpd@esvax.dnet.dupont.com P.O. Box 80328 Tel (302)-695-1757 Wilmington, DE 19880-0328 FAX (302)-695-2112 ----------------------------------------------------------------- =========================================================================== This program takes a set of transtion frequencies and intensities and produces a data set suitable for plotting. By choosing a reasonable valueof HWHM you can create a realistic-looking specturm. The input file should have one transition frequency and intensity per line. -i Input file name of transition frequencies and intensities -o Output file of a plottable spectrum [-l] Lineshape 0 (Lorentzian), 1 (Gaussian), or 2 (Delta function - default) [-h] HWHM (Half-Width at Half-Maximum). Ignored if the lineshape is the delta function [-sc] Frequency scale factor. Multiply all input frequencies by this value. (does not scale HWHM) [-sf] Starting frequency of the output file [-ef] Ending frequency [-fs] Frequency step size. Ignored if the lineshape is the delta function [-d] Sort output by decreasing frequency (default is by increasing frequency) [-n] Normalize intensities to 100 [-nf] Normalization factor. Divide all output intensities by this value. [-wnf] Write the normalization factor to a file. (This allows a factor to be shared among spectra for consistent normalization.) The name of the file is that of the output file with \".nf\" appended. [-w] After generating the spectrum from frequencies in wavenumbers, write the ouput file with wavelengths in nanometers. Quantum mechanics programs such as Gaussian 92, DGAUSS, MNDO91, and MOPAC can calculate vibrational and other transition frequencies. However, these are given as (frequency, intensity) pairs. They have no width and cannot even be plotted directly as a delta function. This program takes those data and creates a more realistic spectrum which is suitable for plotting. The input file should have one frequency and one intensity per line, separated by whitespace (spaces or tabs). The output file has the same format. This program uses only functions included in the ANSI C specification. Paul D. Soper DuPont Central Research & Development E328/123 DUCOM 695-1757