Gilbert Andrew T B, Besley Nicholas A, Gill Peter M W
Research School of Chemistry, Australian National University, ACT 0200, Australia.
J Phys Chem A. 2008 Dec 18;112(50):13164-71. doi: 10.1021/jp801738f.
We present a simple algorithm, which we call the maximum overlap method (MOM), for finding excited-state solutions to self-consistent field (SCF) equations. Instead of using the aufbau principle, the algorithm maximizes the overlap between the occupied orbitals on successive SCF iterations. This prevents variational collapse to the ground state and guides the SCF process toward the nearest, rather than the lowest energy, solution. The resulting excited-state solutions can be treated in the same way as the ground-state solution and, in particular, derivatives of excited-state energies can be computed using ground-state code. We assess the performance of our method by applying it to a variety of excited-state problems including the calculation of excitation energies, charge-transfer states, and excited-state properties.
我们提出了一种简单的算法，我们称之为最大重叠方法（MOM），用于寻找自洽场（SCF）方程的激发态解。该算法不是使用构造原理，而是在连续的SCF迭代中使占据轨道之间的重叠最大化。这可防止变分坍塌到基态，并引导SCF过程朝着最接近的而非能量最低的解进行。所得的激发态解可以与基态解以相同的方式处理，特别是激发态能量的导数可以使用基态代码来计算。我们通过将该方法应用于各种激发态问题，包括激发能、电荷转移态和激发态性质的计算，来评估我们方法的性能。
