Correlation effects in the spectra of polyenes
Correlation effects in the spectra of polyenes
复制标题
多烯光谱中的相关效应
DOI：
10.1063/1.432121
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发表时间：
1976
影响因子：
4.4
通讯作者：
M. Karplus
中科院分区：
文献类型：
--
作者：
K. Schulten;I. Ohmine;M. Karplus
采用Pariser-Parr-Pople形式的哈密顿量研究了关联对多烯π电子能谱的影响。考虑了电子-电子相互作用的两种极限情况（短程和长程极限），并表明它们分别产生对应于标准价键（Dirac-Heisenberg）和分子轨道模型的描述。中间的，化学上最有趣的，范围详细检查通过一个完整的配置相互作用处理与指数模型的潜力，包括一个可变的有效范围参数。结果表明，相关效应变得更加重要的相互作用的有效范围内减少。多烯分子的状态分为共价态和非共价态，发现前者比后者对相关性更敏感。通过双激发的配置相互作用产生一个定性正确的排序的化学范围内的所有状态，但三重和…
A Hamiltonian of the Pariser–Parr–Pople form is employed to investigate the effect of correlation on the π‐electron spectrum of polyenes. Two limiting cases for the electron–electron interaction (short‐ and long‐range limit) are considered, and it is shown that they yield descriptions corresponding to the standard valence‐bond (Dirac–Heisenberg) and molecular‐orbital models, respectively. The intermediate, chemically most interesting, range is examined in detail by means of a full configuration‐interaction treatment with an exponential model potential that includes a variable effective range parameter. It is shown that correlation effects become more important as the effective range of the interaction decreases. The states of polyenes are classified as covalent or noncovalent, and it is found that the former are much more sensitive to correlation than the latter. Configuration interaction through double excitations yields a qualitatively correct ordering for all states in the chemical range, but triple an...