Comparison between standard and counterpoise-corrected optimization using some hydrogen and halogen bonded systems |
| |
Authors: | Ali Ebrahimi Mostafa Habibi Hamid Reza Masoodi |
| |
Affiliation: | 1. Department of Chemistry , University of Sistan?&2. Balouchestan , P.O. Box 98135–674, Zahedan, Iran Ebrahimi@hamoon.usb.ac.ir;4. Balouchestan , P.O. Box 98135–674, Zahedan, Iran |
| |
Abstract: | The effect of the counterpoise correction on the geometries, stabilization energies, and vibrational harmonic frequencies of some hydrogen- and halogen-bonded systems (B?=?CH3CN,?HCN,?NH3,?N2,?CO,?H2O,?H2S,?PH3;?HX?=?HF,?HCl,?HBr,?HCN,?HCF3; XY?=?Br2,?BrCl,?BrF,?Cl2,?ClF,?F2) has been analysed at the MP2 level of theory using the popular 6-311++G(d,p) basis set. The optimized B?···?H and B?···?X bond lengths increase with counterpoise (CP) correction. In some cases standard values and in other cases CP-corrected values are close to experimental data. The absolute values of complexation energies of CP-corrected structures are higher than standard by inclusion of BSSE correction. The effect of CP correction on intermolecular bond lengths and complexation energies of B?···?XY series are usually higher than B?···?HX. Also, this effect is higher for H2S and PH3 groups. The CP correction changes the vibrational harmonic frequencies by 0–100%. The changes are frequently lower than 20% for frequencies higher than 300?cm?1. |
| |
Keywords: | Basis set superposition error Counterpoise Complexation energy Hydrogen bond Vibrational harmonic frequency |
|
|