Chemical Physics Letters, Vol.419, No.4-6, 346-350, 2006
Complex integration steps in decomposition of quantum exponential evolution operators
We generalize previous high-order exponential split operator methods for solving time-dependent Schroedinger equations [A.D. Bandrauk, H. Shen, Chem. Phys. Lett. 176 (1991) 428] by introducing complex integration steps (a + ib) with real positive part a. We show that this new procedure avoids real negative steps which occur generally in high-order split operator methods. New highly accurate splitting schemes are thus derived and the efficiency of these is demonstrated in the calculation of the eigenstates of the one-electron molecular ion H-2(+) (c) 2005 Elsevier B.V. All rights reserved.