Stability of polyatomic molecules in degenerate electronic states. I. Orbital degeneracy
Stability of polyatomic molecules in degenerate electronic states. I. Orbital degeneracy
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DOI：
10.1098/rspa.1937.0142
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发表时间：
1937-07-01
影响因子：
--
通讯作者：
Teller, E
中科院分区：
文献类型：
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作者：
Jahn, HA;Teller, E
下面我们研究当多原子分子的电子态具有轨道简并性时，即多原子分子可以具有稳定平衡构型的条件。 e.简并不是由自旋引起的。我们将证明稳定性和简并性不可能同时存在，除非分子是线性的，即。 e.除非平衡构型中的所有原子核都位于一条直线上。我们还将看到，如果简并性仅仅是由于电子对分子的结合没有太大影响，则不稳定性只是轻微的。我们首先注意到，如果忽略意外简并（即不是由对称引起的简并），那么简并电子态必然需要对称的核构型。因此，为了涵盖所有情况，我们可以首先单独考虑每种可能的对称类型，并讨论哪些核构型与每种对称性一致。给定的分子将拥有一组与一种确定的对称性一致的连续构型，并且在这些构型中可能存在具有最小电子能量的构型。然后，该构型对于所有完全对称的核位移（即不扰乱对称性的位移）而言是稳定的。我们必须研究其相对于所有其他核位移的稳定性。
In the following we investigate the conditions under which a polyatomic molecule can have a stable equilibrium configuration when its electronic state has orbital degeneracy, i. e. degeneracy not arising from the spin. We shall show that stability and degeneracy are not possible simultaneously unless the molecule is a linear one, i. e. unless all the nuclei in the equilibrium configuration lie on a straight line. We shall see also that the instability is only slight if the degeneracy is due solely to electrons having no great influence on the binding of the molecule. We first note that if accidental degeneracy (i. e. degeneracy not caused by symmetry) is disregarded then a degenerate electronic state necessarily entails a symmetrical nuclear configuration. Thus in order to cover all cases we may first consider each possible type of symmetry separately and discuss what nuclear configurations are consistent with each symmetry. A given molecule will possess a continuous set of configurations consistent with one definite type of symmetry, and among these configurations there may be one with a minimum electronic energy. This configuration is then stable with respect to all totally symmetrical nuclear displacements (i. e. displacements which do not disturb the symmetry). We shall have to investigate its stability with respect to all other nuclear displacements.