Following steepest descent reaction paths. The use of higher energy derivatives with a b i n i t i o electronic structure methods

• DOI: 10.1063/1.459634
• Publication Date: 2002-07-26T13:14:51Z
• Authors: Michael Page; Charles Doubleday; James W. McIver
• Keywords: Hamiltonian (control theory)

New methods of determining the steepest descent reaction path in dynamical calculations based on Hamiltonian are investigated. These use first and second energy derivatives correct to third order Taylor series expansion arc length. The H+H2O→H2+OH using small basis set three electron-three active orbital CASSCF wave functions with analytically calculated is used as a test platform. Reaction paths number different step sizes computed their accuracy determined by evaluating deviations curvature from exact RMS deviation transverse frequencies values, criteria more sensitive relevant studies than geometrical parameters. new compared one another computational efficiency accuracy. For this example level theory it found that, addition being accurate at any size, less expensive those that utilize only derivatives.