Intensity Tracking for Vibrational Spectra of Large Molecules

We briefly review our work on theoretical vibrational spectroscopy and elaborate on a recent approach for the selective calculation of high-intensity features in vibrational spectra developed in our laboratory. Conventional methods for the determination of frequencies and intensities describe all vibrations on the same footing, irrespectively of their intensity. This becomes increasingly demanding for larger molecules. In our intensity-driven approach the total intensity is iteratively distributed to individual distinct bands as well as to fingerprint regions so that only the subset of vibrations that dominates the appearance of the spectrum is determined. In turn, normal mode approximations are obtained.