Comparison of the Standard 6-31G and Binning-Curtiss Basis Sets for Third Row Elements
详细信息 查看全文
- 作者：Shahidul M. Islam ; Stephanie D. Huelin ; Margot Dawe ; Raymond A. Poirier
- 刊名：Journal of Chemical Theory and Computation
- 出版年：2008
- 出版时间：January 2008
- 年：2008
- 卷：4
- 期：1
- 页码：86 - 100
- 全文大小：498K
- 年卷期：v.4,no.1(January 2008)
- ISSN：1549-9626
文摘
Ab initio calculations were carried out for isogyric reactions involving the third rowelements, Ga, Ge, As, Se, and Br. Geometries of all the reactants and products were optimizedat the HF, MP2, and B3LYP levels of theory using the 6-31G(d) and 6-31G(d,p) basis sets. Formolecules containing third row elements geometries, frequencies and thermodynamic propertieswere calculated using both the standard 6-31G and the Binning-Curtiss (BC6-31G) basis sets.In order to determine the performance of these basis sets, the calculated thermodynamicproperties were compared to G3MP2 values and where possible to experimental values.Geometries and frequencies calculated with the standard 6-31G and the BC6-31G basis setswere found to differ significantly. Frequencies calculated with the standard 6-31G basis set weregenerally in better agreement with the experimental values (MAD=40.1 cm-1 at B3LYP/6-31G(d,p) and 94.2 cm-1 at MP2/6-31G(d,p) for unscaled frequencies and 29.6 cm-1 and 24.4 cm-1,respectively, for scaled frequencies). For all the reactions investigated, the thermodynamicproperties calculated with the standard 6-31G basis set were found to consistently be in betteragreement with the G3MP2 and the available experimental results. However, the BC6-31G basisset performs poorly for the reactions involving both second and third row elements. Since, ingeneral, the standard 6-31G basis set performs well for all the reactions, we recommend thatthe standard 6-31G basis set be used for calculations involving third row elements. Using G3MP2enthalpies of reaction and available experimental heats of formation (
chars/Delta.gif" BORDER=0 >Hf), previously unknownchars/Delta.gif" BORDER=0 >Hf for CH3SeH, SiH3SeH, CH3AsH2, SiH3AsH2, CH3GeH3, and SiH3GeH3 were found to be18.3, 18.0, 38.4, 82.4, 41.9, and 117.4 kJ mol-1, respectively.
chars/Delta.gif" BORDER=0 >Hf), previously unknownchars/Delta.gif" BORDER=0 >Hf for CH3SeH, SiH3SeH, CH3AsH2, SiH3AsH2, CH3GeH3, and SiH3GeH3 were found to be18.3, 18.0, 38.4, 82.4, 41.9, and 117.4 kJ mol-1, respectively.