This work was supported by the U.S. Air Force Office of Scientific Research under Grant No. 121606083.
Analytical gradients for the coupled-cluster method†
Article first published online: 16 APR 2008
Copyright © 1984 John Wiley & Sons, Inc.
International Journal of Quantum Chemistry
Supplement: Atomic, Molecular and Solid-State Theory, and Computational Quantum Chemistry
Volume 26, Issue Supplement 18, pages 245–254, 1/15 March 1984
How to Cite
Adamowicz, L., Laidig, W. D. and Bartlett, R. J. (1984), Analytical gradients for the coupled-cluster method. Int. J. Quantum Chem., 26: 245–254. doi: 10.1002/qua.560260825
- Issue published online: 16 APR 2008
- Article first published online: 16 APR 2008
- Manuscript Received: 21 MAY 1984
A nondiagrammatic formulation of the analytical first derivative of the coupled-cluster (CC) energy with respect to nuclear position is presented and some features of an efficient computational method to calculate this derivative are described. Since neither the orbitals nor the configuration expansion coefficients are variationally determined, in the most general case derivatives of both are necessary in computing the gradient. This requires the initial solution of the coupled perturbed Hartree-Forck (CPHF) equations and seems to mandate the solution of a linear matrix equation ZT(1) = X for first-order corrections to the CC coefficients. However, if only the analytic gradient is desired a simpler non-perturbation-dependent set of equations can be solved instead. This and the first-order character of the linear matrix equation makes the application of an analytic gradient technique to the CC method feasible.