Single-reference Moller-Plesset perturbation extrapolation technique in the accurate model chemistry is unreliable for non-equilibrium molecules
文献类型：期刊论文
| 作者 | Xu, KH; Wei, J; Hu, XL; Yue, H; Lu, L; Wang, YB; Wen, ZY |
| 刊名 | ACTA PHYSICO-CHIMICA SINICA
 |
| 出版日期 | 2000-10-01 |
| 卷号 | 16页码:912-919 |
| 关键词 | single reference state Moller-Plesset perturbation extrapolation model chemistry non-equilibrium structure unreliable |
| ISSN号 | 1000-6818 |
| DOI | 10.3866/PKU.WHXB20001009 |
| 英文摘要 | Potential energy curves of BH((1) Sigma) and AlH((1)Sigma) molecules in their ground electronic states were calculated at RQCISD(T), UQCISD(T), BCCSD(T), UCCSD(T) and CASSCF (with four active electrons in five active orbitals) theoretical levels, Basis sets examined were 6-311 +G (3 df, 2p), G3 large, aug-cc-pVDZ and aug-cc-pVTZ and the bond lengths tested were up to 1.0 nm: Potential energy curves of BF((1)Sigma) and AlF((1)Sigma) were also examined at MP4/aug-cc-pVDZ level. It was shown that the MPn (n = 2 - 4) curves for BH, AlH and BF were seriously in error. in accordance with CASSCF wavefunctions, the single Hartree-Fock reference state was insufficient to describe the electronic structure of these molecules. In this case, the Hartree-Fock energy gaps between the LUMO and HOMO orbitals for these molecules were decreased when the bond distances were increased. By examination of the molecular orbital integrals, it was found that the interaction (integral values) between HOMO and LUMO orbitals increased greatly. As in the case of second-order MP perturbation calculations, the "stronger interaction" and the "smaller energy gap" resulted in too large correlation energy corrections and therefore led to serious errors in the total electronic energy. This predicted clearly that the MPn extrapolation technique in the widely used G1, G2, G3 and CBS series accurate model chemistry was not reliable in general if the molecule is not at its equilibrium geometry, as what in the study of chemical reaction paths. However, QCISD(T) calculations reflected approximately the correct potential energy curves and more reliable dissociation limits. The maximum error, 40.6 kJ.mol(-1), of dissociation energy at the bond length of 1.0 nm was found in AlH molecule by the G2 basis sets 6-311 + G(3 df, 2p). The CCSD(T) was also found less reliable than the QCISD(T) method in describing the dissociation energies. The same error was 101.9 kJ.mol(-1). All of the results in this work suggested the non-extrapolation G2(QCI) be more reliable a method in the energy calculations of non-equilibrium structure of molecules and be more valuable in further developments and modifications to the methods of accurate model chemistry. |
| WOS关键词 | QUADRATIC CONFIGURATION-INTERACTION ; DENSITY-FUNCTIONAL GEOMETRIES ; GAUSSIAN-2 THEORY ; CORRELATION ENERGIES ; 2ND-ROW COMPOUNDS ; ATOMS ; 1ST-ROW |
| WOS研究方向 | Chemistry |
| 语种 | 英语 |
| WOS记录号 | WOS:000168532200009 |
| 出版者 | PEKING UNIV PRESS |
| 源URL | [http://119.78.100.186/handle/113462/36373]  |
| 专题 | 中国科学院近代物理研究所 |
| 通讯作者 | Xu, KH |
| 作者单位 | 1.Northwestern Polytech Univ, Dept Chem Engn, Xian 710072, Peoples R China 2.Northwwest Univ, Inst Modern Phys, Xian 710068, Peoples R China |
| 推荐引用方式 GB/T 7714 | Xu, KH,Wei, J,Hu, XL,et al. Single-reference Moller-Plesset perturbation extrapolation technique in the accurate model chemistry is unreliable for non-equilibrium molecules[J]. ACTA PHYSICO-CHIMICA SINICA,2000,16:912-919. |
| APA | Xu, KH.,Wei, J.,Hu, XL.,Yue, H.,Lu, L.,...&Wen, ZY.(2000).Single-reference Moller-Plesset perturbation extrapolation technique in the accurate model chemistry is unreliable for non-equilibrium molecules.ACTA PHYSICO-CHIMICA SINICA,16,912-919. |
| MLA | Xu, KH,et al."Single-reference Moller-Plesset perturbation extrapolation technique in the accurate model chemistry is unreliable for non-equilibrium molecules".ACTA PHYSICO-CHIMICA SINICA 16(2000):912-919. |
入库方式： OAI收割
来源：近代物理研究所
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