Anharmonic potential functions as derived from Raman intensities: Methane

Analytic calculations of anharmonic infrared and Raman vibrational spectra

Using a recently developed recursive scheme for the calculation of high-order geometric derivatives of frequency-dependent molecular properties [Ringholm et al., J. Comp. Chem., 2014, 35, 622], we present the first analytic calculations of anharmonic infrared (IR) and Raman spectra including anharmonicity both in the vibrational frequencies and in the IR and Raman intensities. In the case of an...

Effects of extracts derived from pistachio by-products on ruminal fermentation and methane production

The objective of this study was to evaluate the effects of different doses of pistachio by-product (PBP) extracts supplemented with alfalfa hay (AH) or barley grain (BG) on microbial fermentation in an in vitro fermentation system. The total extracted phenolic compounds were 36.96, 65.78, 67.02 and 8.85% and total extracted tannin contents were 37.11, 59.64, 56.87 and 7.55% when PBP was extract...

Vibrational Distribution Functions in Anharmonic Oscillators

A model has been developed to calculate the steady state vibrational distribution of an anharmonic oscillator under conditions of thermal nonequilibrium. The model includes vibration-vibration and vibrationtranslation collisional processes as well as radiative decay. Numerical calculations are shown to be in reasonably good agreement with experimental data obtained in electrically excited N^-CO...

Ab-initio Raman spectra of anharmonic and disordered systems

Anharmonic effects in IR, Raman, and Raman optical activity spectra of alanine and proline zwitterions.

The difference spectroscopy of the Raman optical activity (ROA) provides extended information about molecular structure. However, interpretation of the spectra is based on complex and often inaccurate simulations. Previously, the authors attempted to make the calculations more robust by including the solvent and exploring the role of molecular flexibility for alanine and proline zwitterions. In...