Buren Bayaer, Chen Maodu, Sun Zhigang, Guo Hua
Key Laboratory of Materials Modification by Laser, Electron, and Ion Beams (Ministry of Education), School of Physics, Dalian University of Technology, Dalian 116024, China.
Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, United States.
J Phys Chem A. 2021 Nov 25;125(46):10111-10120. doi: 10.1021/acs.jpca.1c08105. Epub 2021 Nov 12.
Cold and ultracold collisions are dominated by quantum effects, such as resonances, tunneling, and nonadiabatic transitions between different electronic states. Due to the extremely long de Broglie wavelength in such processes, quantum reactive scattering is most conveniently characterized using the time-independent close-coupling (TICC) methods. However, the TICC approach is difficult for systems with a large number of channels because of its steep numerical scaling laws. Here, a recently proposed quantum wave packet (WP) approach for solving adiabatic reactive scattering problems at low collision energies is extended to include nonadiabatic transitions. To impose the outgoing boundary conditions, the total scattering wavefunction is split into three parts, the interaction, the asymptotic, and the long-range regions. Each region is associated with a different set of basis functions, which could be optimized separately. In this way, an extremely long grid can be used to accommodate the characteristic long de Broglie wavelengths in the scattering coordinate. The better numerical scaling laws of the WP approach have the potential for handling larger nonadiabatic reactive systems at low temperatures in the future.
冷碰撞和超冷碰撞由量子效应主导，例如共振、隧穿以及不同电子态之间的非绝热跃迁。由于此类过程中德布罗意波长极长，量子反应散射最适合用含时密耦（TICC）方法来表征。然而，TICC方法对于具有大量通道的系统而言存在困难，因为其数值标度律很陡。在此，一种最近提出的用于求解低碰撞能量下绝热反应散射问题的量子波包（WP）方法被扩展到包含非绝热跃迁。为施加出射边界条件，总散射波函数被分为三部分：相互作用区域、渐近区域和长程区域。每个区域与一组不同的基函数相关联，这些基函数可分别进行优化。通过这种方式，可使用极长的网格来适应散射坐标中特征性的长德布罗意波长。WP方法更好的数值标度律有望在未来处理更大的低温非绝热反应系统。
