STRUCTURAL AND ELECTRONIC-PROPERTIES OF INFINITE CIS AND TRANS POLYENES - PERTURBATION-THEORY OF ELECTRON CORRELATION-EFFECTS
STRUCTURAL AND ELECTRONIC-PROPERTIES OF INFINITE CIS AND TRANS POLYENES - PERTURBATION-THEORY OF ELECTRON CORRELATION-EFFECTS
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DOI：
10.1002/qua.560420112
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发表时间：
1992-04-05
影响因子：
2.2
通讯作者：
SUHAI, S
中科院分区：
文献类型：
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作者：
SUHAI, S
利用hartrei - fock水平上的三种不同原子基集，并在Moller-Plesset微扰理论的二阶范围内包含电子相关效应，对五种无限多烯模型（等距交替反式、等距顺式、顺-反式和反-顺式）的几何结构进行了优化。用电子极化子方法对单粒子能带的相关效应进行了校正。键的交替总是降低多烯的能量（对反式和顺式都是如此），但这种稳定能量随着基集的增加而降低，在反式和反式顺斜面模型中达到约3mh的饱和，在顺-反斜面模型中达到约7.5 mH的饱和。绝对的能源规模,然而,交替反式结构一直被证明是比cis-transoid或更稳定trans-cisoid。在所有情况下，能量顺序都是横贯<顺-横贯<横贯。使用最大的相关基集，对应的能量差分别为DELTA-E(trans -> trans-cisoid) = 1.69 mH和DELTA-E(trans -> trans-cisoid) = 6.12 mH。顺式模型的价带宽度HF值在4 ~ 6 eV范围内变化，反式模型的价带宽度HF值约为7 eV。相关性降低了约20%，并且由于自能量重整化，能带中心向上移动了约2ev。交替反式、反顺式、顺-顺式和等距顺式模型的电子极化子价宽最佳值分别为6.4、4.2、3.3和5.2 eV。这四种结构的垂直电离势分别为4.80、5.47、5.71和4.18 eV。在HF水平上，导带的宽度为6-8 eV（较大基集的等距顺式为4.6 eV除外），由于极化子的形成，导带的宽度将减少约15-20%。在这种情况下，由于相关性，波段均匀向下移动约2-3 eV。导通带宽的最佳值分别为4.7、6.4、5.6和3.7 eV。这些带移使所有模型的基隙的HF值降低了几个eV。对于最大的基集，DELTA-E（间隙）值在相关水平上分别从6.6、6.9、7.7和5.3 eV（交替反式、反-顺式、顺-顺式和等距顺式模型的HF结果）变化到2.7、3.2、4.5和2 eV。
The geometrical structure of five infinite polyene models (equidistant and alternating trans, equidistant cis, cis-transoid, and trans-cisoid) have been optimized using three different atomic basis sets at the Hartree-Fock level and by including electron correlation effects within the second order of Moller-Plesset perturbation theory. The single-particle energy bands have also been corrected for correlation effects applying the electron polaron method. Bond alternation has always reduced the energy (both for trans and cis) polyenes but this stabilization energy has decreased with an increasing basis set and has saturated about 3 mH for trans and trans-cisoid and about 7.5 mH for the cis-transoid model. On the absolute energy scale, however, the alternating trans structure has always turned out to be more stable than either the cis-transoid or the trans-cisoid one. The energetic order is in all cases trans < cis-transoid < trans-cisoid. Using the largest basis set with correlation, the corresponding energy differences are DELTA-E(trans --> cis-transoid) = 1.69 mH and DELTA-E(trans --> trans-cisoid) = 6.12 mH, respectively. The HF values of the valence-band widths vary in the region of 4-6 eV for the cis models and about 7 eV for the trans one. Correlation reduced them by about 20%, and the centers of the bands were shifted upward by about 2 eV due to self-energy renormalization. The best values for the electron polaron valence bandwidths are 6.4, 4.2, 3.3, and 5.2 eV for the alternating trans, trans-cisoid, cis-transoid, and equidistant cis models, respectively. The vertical ionization potentials of the above four structures are 4.80, 5.47, 5.71, and 4.18 eV, respectively. The conduction bands have a width of 6-8 eV at the HF level (except equidistant cis with 4.6 eV for the larger basis sets) that will be reduced by about 15-20% due to polaron formation. The bands are shifted in this case uniformly downward by about 2-3 eV due to correlation. The best values obtained for the conduction bandwidths are 4.7, 6.4, 5.6, and 3.7 eV, respectively. These band shifts reduce the HF value of the fundamental gap by several eV's for all models. For the largest basis set, the DELTA-E(gap) values change from 6.6, 6.9, 7.7, and 5.3 eV (HF results for the alternating trans, trans-cisoid, cis-transoid, and equidistant cis models, respectively) to 2.7, 3.2, 4.5, and 2 eV, respectively, at the correlated level.