The ONIOM (our own N-layered integrated molecular orbital plus molecular mechanics) method for the first singlet excited (S1) state photoisomerization path of a retinal protonated Schiff base
The ONIOM (our own N-layered integrated molecular orbital plus molecular mechanics) method for the first singlet excited (S1) state photoisomerization path of a retinal protonated Schiff base
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DOI：
10.1063/1.1287059
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发表时间：
2000-08-22
影响因子：
4.4
通讯作者：
Morokuma, K
中科院分区：
文献类型：
--
作者：
Vreven, T;Morokuma, K
通过测试大量的ONIOM（我们自己的N层积分分子轨道+分子力学）组合对标准完全活性空间自洽场（CASSCF）方法与6- 31 G（d）基组，我们已经调查了ONIOM的适用性（分子轨道+分子轨道）方法研究第一单重激发态（S-1）质子化席夫碱（PSB）中的光异构化途径。对于11-非氢（H）PSB（10-非H Schiff碱加一个甲基）的异构化反应，ONIOM仅用10%的计算机时间就能准确地再现标准CASSCF（10 e/10 o）（10个活泼电子在10个轨道上）的结果。模型体系，其中包括质子化的席夫碱基团以及异构化键，总是在CASSCF水平上处理。在低能级下，用非限制性Hartree-Fock第一三重态（T-1）精确地再现了S-1的能量分布，而在低能级下，用含时Hartree-Fock或单激发组态相互作用很好地再现了单重基态（S-0）和S-1态之间的差异.使用我们的ONIOM方法，我们还计算了整个视网膜质子化席夫碱的第一个S-1异构化能量分布。(C)2000年美国物理学会。[S0021-9606（00）30532-3]。
By testing a large number of ONIOM (our own N-layered integrated molecular orbital + molecular mechanics) combinations against the standard complete active space self-consistent field (CASSCF) method with the 6-31G(d) basis set, we have investigated the suitability of the ONIOM (molecular orbital + molecular orbital) method for the investigation of the first singlet excited state (S-1) photoisomerization pathways in protonated Schiff bases (PSBs). For the isomerization reaction of an 11-nonhydrogen (H) PSB (10-non-H Schiff base plus one methyl group), ONIOM can accurately reproduce the standard CASSCF(10e/10o) (10 active electrons in 10 orbitals) results for only 10% of the computer time. The model system, which includes the protonated Schiff base group as well as the isomerization bond, was always treated at the CASSCF level. With the unrestricted Hartree-Fock first triplet state (T-1) in the low level, the S-1 energy profile is reproduced accurately, while time-dependent Hartree-Fock or single excitation configuration interaction in the low level reproduces the difference between the singlet ground state (S-0) and S-1 states very well. Using our ONIOM method, we also computed the first S-1 isomerization energy profile of the entire retinal protonated Schiff base. (C) 2000 American Institute of Physics. [S0021-9606(00)30532-3].