Theoretical study of the vibrational frequencies of carbon disulfide

A benchmark comparison for different computational methods and basis sets has been presented. In this study, five computational methods (Hartree–Fock (HF), MP2, B3LYP, MPW1MP91, and PBE1PBE) along with 18 basis sets have been applied to optimize the geometry of carbon disulfide (CS2), and further calculate the vibrational frequencies of the optimized geometries. The differences between the calculated frequencies and corresponding experimental data are used to evaluate the efficiency of each combination of computational method and basis set. The comparison of frequency difference indicates that B3LYP generally gives the best prediction of frequencies for CS2, whereas the other two density functional theory (DFT) methods, i.e., MPW1PW91 and PBE1PBE, often give parallel results. Although MP2 predicts the frequencies with accuracy almost as good as those from DFT methods, in a particular case, HF calculation outperforms MP2 as well as MPW1PW91 and PBE1PBE for prediction of the frequency of asymmetrical stretching for CS2. © 2013 Wiley Periodicals, Inc. Model molecules are often used in benchmark calculations to identify the most appropriate computational approach for describing specific physical properties. Calculations of the vibrational frequencies of CS2 using a combination of theoretical methods and basis sets validate the use of B3LYP and MP2 as the most accurate approaches. Although Hartree–Fock generally overestimates the frequency, it outperforms MP2 and some DFT functionals in predicting the frequency for asymmetric stretching.