title: Parallelization strategy for large-scale vibronic coupling calculations.
abstract: The vibronic coupling model of Köppel, Domcke, and Cederbaum is a powerful means to understand, predict, and analyze electronic spectra of molecules, especially those that exhibit phenomena that involve breakdown of the Born-Oppenheimer approximation. In this work, we describe a new parallel algorithm for carrying out such calculations. The algorithm is conceptually founded upon a "stencil" representation of the required computational steps, which motivates an efficient strategy for coarse-grained parallelization. The equations involved in the direct-CI type diagonalization of the model Hamiltonian are presented, the parallelization strategy is discussed in detail, and the method is illustrated by calculations involving direct-product basis sets with as many as 17 vibrational modes and 130 billion basis functions.
authors.affiliation: Institute for Computational Engineering and Sciences, The University of Texas at Austin , Austin, Texas 78712, United States.
authors.forename: Scott M
authors.initials: SM
authors.lastname: Rabidoux
authors.forename: Victor
authors.initials: V
authors.lastname: Eijkhout
authors.forename: John F
authors.initials: JF
authors.lastname: Stanton