Department of Chemistry, Chemical Theory Center, and Minnesota Supercomputing Institute, University of Minnesota, 207 Pleasant Street SE, Minneapolis, MN 55455-0431, USA.
Phys Chem Chem Phys. 2018 Nov 7;20(41):26643-26659. doi: 10.1039/c8cp03410a. Epub 2018 Oct 15.
Diabatization converts adiabatic electronic states to diabatic states, which can be fit with smooth functions, thereby decreasing the computational time for simulations. Here we present a new diabatization scheme based on components of the nonadiabatic couplings and the adiabatic energy gradients. The nonadiabatic couplings are multi-dimensional vectors that are singular along conical intersection seams, and this makes them essentially impossible to fit; furthermore they have unphysical aspects due to the assumptions of the generalized Born-Oppenheimer scheme, and therefore they are not usually used in diabatization schemes. However, we show here that the nonadiabatic couplings can provide a route to obtaining diabatic states by using the sign change of the energy gradient differences of adiabatic states on paths through conical intersections or locally avoided crossings. We present examples applying the method successfully to several test systems. We compare the method to other diabatization methods previously developed in our group.
绝热态到非绝热态的转变称为绝热化，它可以通过平滑函数进行拟合，从而减少模拟的计算时间。在此，我们提出了一种新的基于非绝热耦合分量和绝热能量梯度的绝热化方案。非绝热耦合是多维向量，在圆锥交叉线上奇异，这使得它们本质上无法拟合；此外，由于广义 Born-Oppenheimer 方案的假设，它们具有非物理的方面，因此它们通常不用于绝热化方案。然而，我们在这里表明，非绝热耦合可以通过使用穿过圆锥交叉点或局部避免交叉点的绝热态的能量梯度差的符号变化来提供获得非绝热态的途径。我们提出了成功应用该方法的几个测试系统的例子。我们将该方法与我们小组之前开发的其他绝热化方法进行了比较。
