This window displays synthetic spectra, either infrared (absorption downward) or Raman and NRVS (scattering upward), or both. It appears or is refreshed after a calculation if the Spectra Plot box is checked in the Control Window.
See the complete list of Menu options
Individual modes are shown as vertical bars. The Parameters button brings up the Spectra Plot Parameters dialog, for setting of several parameters which influence the appearance of the spectra.
The Isoconfig (Isotope Configuration) spin control selects which isotope configuration is being shown in this window - the base configuration (no isotope substitutions) is number 1.
The Output combo box allows file or printed output (these options are also in the File menu for the window). The Print Current option will print an image of the current spectra; the Print All option will print all the polarized components (not the averages) in pairs, in the order listed in the combo boxes. Since the Print option in the File menu prints different things depending on which window is active (Output file Text window; Spectra; Atoms), using these buttons insures that the Spectra image is printed.
For degenerate species only one of the (identical) allowed components is present. Generally, x is preferred over y and z, xx-yy over xy, and xz over xy and yz.
The Infrared and Raman combo boxes allow selection of average spectra, individual species and polarization components, or no spectra.
For the Raman spatially averaged spectrum the upper curve represents the parallel polar orientation, and the lower curve the perpendicular polar orientation. The lower curve is simply obtained by multiplying the calculated Raman intensity of each mode by its depolarization ratio (see Theory and Implementation).
The NRVS (nuclear resonant vibrational spectroscopy) spectrum tracks the motions of certain nuclei, especially 57Fe, which are subject to a certain kind of gamma-ray (or X-ray) absorption. As implemented in VIBRATZ, an NRVS spectrum shows a peak for each vibrational mode in which the 57Fe atoms move, and the intensity is proportional to the fraction of kinetic energy in the iron atoms. VIBRATZ identifies iron atoms (assumed to be isotope 57) as any atoms with type number 26 mod 100 (26, 126, 226...). The standard atom type number 26 has natural atomic weight, so for very precise results the weight of any atom types involved should be changed to 57. If an NRVS spectrum for any other isotope is necessary, that atom(s) can simply be assigned type number 26 mod 100. Type number 26 should then be given the actual atomic weight for this isotope.
If the PED (potential energy distribution) box is checked, the lowermost plot will show as many as four curves, each with the fractional contribution to the energy of modes from an FCON, or group of FCONs. The color of each curve, and the FCONs which are included in each, are set with the Spectra Plot Parameters dialog, called with the Parameters button. The curves may represent raw fractions of the energy at each mode, or the weighted intensity for infrared, Raman or NRVS, as selected with the Mode parameter in the Spectra Plot Parameters dialog.
The maximum positive fraction is printed out on the top line of a legend in the upper left of the PED section of the window - this number may represent raw fractions of the energy at each mode, or the weighted intensity for infrared, Raman or NRVS, as selected with the Mode parameter in the Spectra Plot Parameters dialog. The second and successive lines give in parentheses the FCONs which contribute to each curve.