Gumber Shriya, Prezhdo Oleg V
Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States.
Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089, United States.
J Phys Chem Lett. 2023 Aug 17;14(32):7274-7282. doi: 10.1021/acs.jpclett.3c01831. Epub 2023 Aug 9.
Decoherence plays an important role in nonadiabatic (NA) molecular dynamics (MD) simulations because it provides a physical mechanism for trajectory hopping and can alter transition rates by orders of magnitude. Generally, decoherence effects slow quantum transitions, as exemplified by the quantum Zeno effect: in the limit of infinitely fast decoherence, the transitions stop. If the measurements are not sufficiently frequent, an opposite quantum anti-Zeno effect occurs, in which the transitions are accelerated with faster decoherence. Using two common NA-MD approaches, fewest switches surface hopping and decoherence-induced surface hopping, combined with analytic examination, we demonstrate that including decoherence into NA-MD slows down NA transitions; however, many realistic systems operate in the anti-Zeno regime. Therefore, it is important that NA-MD methods describe both Zeno and anti-Zeno effects. Numerical simulations of charge trapping and relaxation in graphitic carbon nitride suggest that time-dependent NA Hamiltonians encountered in realistic systems produce robust results with respect to errors in the decoherence time, a favorable feature for NA-MD simulations.
退相干在非绝热（NA）分子动力学（MD）模拟中起着重要作用，因为它为轨迹跳跃提供了一种物理机制，并且可以使跃迁速率改变几个数量级。一般来说，退相干效应会减缓量子跃迁，量子芝诺效应就是一个例子：在无限快退相干的极限情况下，跃迁会停止。如果测量不够频繁，就会出现相反的量子反芝诺效应，即跃迁会随着退相干加快而加速。通过使用两种常见的NA-MD方法，即最少开关表面跳跃法和退相干诱导表面跳跃法，并结合分析研究，我们证明将退相干纳入NA-MD会减缓NA跃迁；然而，许多实际系统处于反芝诺 regime。因此，NA-MD方法能够描述芝诺效应和反芝诺效应是很重要的。石墨相氮化碳中电荷俘获和弛豫的数值模拟表明，实际系统中遇到的含时NA哈密顿量对于退相干时间的误差会产生稳健的结果，这是NA-MD模拟的一个有利特征。
