Pan, W; Lee, T-S; Yang, W, *Parallel implementation of divide-and-conquer semiempirical quantum chemistry calculations*,
Journal of Computational Chemistry, vol. 19 no. 9
(1998),
pp. 1101-1109 .
**Abstract:**

*We have implemented a parallel divide-and-conquer method for semiempircal quantum mechanical calculations. The standard message passing library, the message passing interface (MPI), was used. In this parallel version, the memory needed to store the Fock and density matrix elements is distributed among the processors. This memory distribution solves the problem of demanding requirement of memory for very large molecules. While the parallel calculation for construction of matrix elements is straightforward, the parallel calculation of Fock matrix diagonalization is achieved via the divide-and-conquer method. Geometry optimization is also implemented with parallel gradient calculations. The code has been tested on a Cray T3E parallel computer, and impressive speedup of calculations has been achieved. Our results indicate that the divide-and-conquer method is efficient for parallel implementation. © 1998 John Wiley & Sons, Inc.*