Nonadiabatic decay of metastable states on coupled linear potentials
Nonadiabatic decay of metastable states on coupled linear potentials
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DOI：
10.1088/1367-2630/ac6ca2
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发表时间：
2022-01
影响因子：
3.3
通讯作者：
A. Duspayev;Ansh Shah;G. Raithel
中科院分区：
文献类型：
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作者：
A. Duspayev;Ansh Shah;G. Raithel
具有相反斜率的能级对的避免交叉可以形成量子粒子外部自由度的势能最小值，在避免交叉（MSACs）上产生亚稳态。通过求解绝热和绝热两种形式的双组分Schrödinger方程，研究了msac的非绝热衰变。通过计算非时变解的波函数通量和散射相位，以及时变解的波函数衰减，得到了非摄动寿命值。从这些方法得到的值总体上一致，验证了所采用的方法。当系统的绝热参数V在绝热/绝热混合状态下增加约10倍时，MSAC特征从边缘稳定转变为高度稳定，寿命增加约10个数量级。本文讨论了几种V状态下MSAC寿命与振动量子数ν的关系。在V和ν的研究范围内，时间相关的微扰理论得出的寿命与非微扰结果相差约30%，而基于朗道-齐纳隧穿的半经典模型则相差20倍。这些结果与许多具有亚稳态的原子和分子系统有关，这些系统位于相交的耦合势能曲线上。
Avoided crossings of level pairs with opposite slopes can form potential-energy minima for the external degree of freedom of quantum particles, giving rise to metastable states on the avoided crossings (MSACs). Nonadiabatic decay of MSACs is studied by solving the two-component Schrödinger equation in diabatic and adiabatic representations. Non-perturbative lifetime values are found by evaluating wave function flux and scattering phases of time-independent solutions, as well as wave-function decay of time-dependent solutions. The values from these methods generally agree well, validating the utilized approaches. As the adiabaticity parameter, V, of the system is increased by about a factor of ten across the mixed diabatic/adiabatic regime, the MSAC character transitions from marginally to highly stable, with the lifetimes increasing by about ten orders of magnitude. The dependence of MSAC lifetime on the vibrational quantum number, ν, is discussed for several regimes of V. Time-dependent perturbation theory yields lifetimes that deviate by ≲30% from non-perturbative results, over the range of V and ν studied, while a semi-classical model based on Landau–Zener tunneling is up to a factor of twenty off. The results are relevant to numerous atomic and molecular systems with metastable states on intersecting, coupled potential energy curves.