An Evaluation of Harmonic Vibrational Frequency Scale Factors Export

@article{citeulike:6073519, abstract = {PMID: 17948971 Scale factors for obtaining fundamental vibrational frequencies, low-frequency vibrational frequencies, zero-point vibrational energies (ZPVEs), and thermal contributions to enthalpy and entropy have been derived through a least-squares approach from harmonic frequencies determined at more than 100 levels of theory. Wave function procedures (HF, MP2, QCISD, QCISD(T), CCSD, and CCSD(T)) and a large and representative range of density functional theory (DFT) approaches (B3-LYP, BMK, EDF2, M05-2X, MPWB1K, O3-LYP, PBE, TPSS, etc.) have been examined in conjunction with basis sets such as 6-31G(d), 6-31+G(d,p), 6-31G(2df,p), 6-311+G(d,p), and 6-311+G(2df,p). The vibrational frequency scale factors were determined by a comparison of theoretical harmonic frequencies with the corresponding experimental fundamentals utilizing a standard set of 1066 individual vibrations. ZPVE scale factors were generally obtained from a comparison of the computed ZPVEs with experimental ZPVEs for a smaller standard set of 39 molecules, though the effect of expansion to a 48 molecule data set was also examined. In addition to evaluating the scale factors for a wide range of levels of theory, we have also probed the effect on scale factors of varying the percentage of incorporated exact exchange in hybrid DFT calculations using a modified B3-LYP functional. This has revealed a near-linear relationship between the magnitude of the scale factor and the proportion of exact exchange. Finally, we have investigated the effect of basis set size on HF, MP2, B3-LYP, and BMK scale factors by deriving values with basis sets ranging from 6-31G(d) up to 6-311++G(3df,3pd) as well as with basis sets in the cc-pVnZ and aug-cc-pVnZ series and with the TZV2P basis.}, author = {Merrick, Jeffrey P. and Moran, Damian and Radom, Leo}, citeulike-article-id = {6073519}, citeulike-linkout-0 = {http://dx.doi.org/10.1021/jp073974n}, citeulike-linkout-1 = {http://pubs.acs.org/doi/abs/10.1021/jp073974n}, day = {1}, doi = {10.1021/jp073974n}, journal = {The Journal of Physical Chemistry A}, keywords = {frequency, harmonic, scaling, vibrational, zpve}, month = {November}, number = {45}, pages = {11683--11700}, posted-at = {2009-11-05 10:40:04}, priority = {2}, title = {An Evaluation of Harmonic Vibrational Frequency Scale Factors}, url = {http://dx.doi.org/10.1021/jp073974n}, volume = {111}, year = {2007} }

TY - JOUR ID - citeulike:6073519 L3 - citeulike-article-id:6073519 N2 - PMID: 17948971 Scale factors for obtaining fundamental vibrational frequencies, low-frequency vibrational frequencies, zero-point vibrational energies (ZPVEs), and thermal contributions to enthalpy and entropy have been derived through a least-squares approach from harmonic frequencies determined at more than 100 levels of theory. Wave function procedures (HF, MP2, QCISD, QCISD(T), CCSD, and CCSD(T)) and a large and representative range of density functional theory (DFT) approaches (B3-LYP, BMK, EDF2, M05-2X, MPWB1K, O3-LYP, PBE, TPSS, etc.) have been examined in conjunction with basis sets such as 6-31G(d), 6-31+G(d,p), 6-31G(2df,p), 6-311+G(d,p), and 6-311+G(2df,p). The vibrational frequency scale factors were determined by a comparison of theoretical harmonic frequencies with the corresponding experimental fundamentals utilizing a standard set of 1066 individual vibrations. ZPVE scale factors were generally obtained from a comparison of the computed ZPVEs with experimental ZPVEs for a smaller standard set of 39 molecules, though the effect of expansion to a 48 molecule data set was also examined. In addition to evaluating the scale factors for a wide range of levels of theory, we have also probed the effect on scale factors of varying the percentage of incorporated exact exchange in hybrid DFT calculations using a modified B3-LYP functional. This has revealed a near-linear relationship between the magnitude of the scale factor and the proportion of exact exchange. Finally, we have investigated the effect of basis set size on HF, MP2, B3-LYP, and BMK scale factors by deriving values with basis sets ranging from 6-31G(d) up to 6-311++G(3df,3pd) as well as with basis sets in the cc-pVnZ and aug-cc-pVnZ series and with the TZV2P basis. IS - 45 JF - The Journal of Physical Chemistry A EP - 11700 TI - An Evaluation of Harmonic Vibrational Frequency Scale Factors VL - 111 SP - 11683 KW - frequency KW - harmonic KW - scaling KW - vibrational KW - zpve AU - Merrick, Jeffrey AU - Moran, Damian AU - Radom, Leo PY - 2007/11/01/ UR - http://dx.doi.org/10.1021/jp073974n ER -