Semiclassical methods in multiphoton diatomic spectroscopy: beyond perturbation theory
Semiclassical methods in multiphoton diatomic spectroscopy: beyond perturbation theory
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多光子双原子光谱中的半经典方法：超越微扰理论
DOI：
10.1021/j100310a011
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发表时间：
1987
期刊：
影响因子：
--
通讯作者：
O. Atabek
中科院分区：
文献类型：
--
作者：
A. Bandrauk;O. Atabek
双原子分子中的电子扰动通常涉及电子态之间的耦合，这种耦合在这些态的势曲线的交叉点或交叉点附近是最重要的。这样的扰动通常被称为非辐射的，交叉的情况被称为绝热的，因为它涉及到某些电子耦合的忽略（州际电子，自旋轨道等），或者绝热的，避免交叉的情况。1,2在后一种情况下，上述州际非绝热电子耦合已经包括在内，其余的耦合是非绝热型的，涉及绝热电子波函数的核坐标导数。这些非绝热耦合是总动量守恒定律的结果。这一定律在绝热近似中是违反的，因为绝热电子函数是在固定的核位置上计算的，即在零核动量下。束缚态之间的扰动通常可以通过对角化非绝热或绝热表示的有限尺寸哈密顿矩阵来处理。当连续态介入时，更困难的扰动就会发生。例如，界连续统扰动总是出现在预解问题中。对于后一类问题，
Electronic perturbations in diatomic molecules generally involve couplings between electronic states which are most important at crossings or near crossings of the potential curves of these states. Such perturbations are usually termed nonradiative, with the crossing case called diabatic, as it involves the neglect of certain electronic couplings (interstate electronic, spin-orbit, etc.), or adiabatic, the case of avoided crossings. 1, 2 In the latter case, the interstate diabatic electronic couplings referred to above havebeen included, and the remaining couplings are of the nonadiabatic type, involving nuclear coordinate derivatives of adiabatic electronic wavefunctions. These nonadiabatic couplings are a consequence of the law of conservation of totalmomentum. This law is violated in the adiabatic approximation since the adiabatic electronic functions are calculated at fixed nuclear positions, ie, at zero nuclear momentum. 1 23 4" 5 Perturbations between bound states can be usually treated by diagonalizing finite-size Hamiltonian ma-trices in the diabatic or adiabatic representation. 2 The more difficult perturbations occur whenever continuum states intervene. For instance, bound-continuum perturbations arise always in problems of predissociation. 1, 2 For the latter type of problems,