Accelerated ab initio molecular dynamics with response equation extrapolation

Polynomial extrapolation of response (‘z-vector’) elements is shown to reduce the cost of correlated-wavefunction, classical ab initio molecular dynamics. Demonstrations with resolution-of-the-identity Moller–Plesset perturbation theory (RI-MP2) show that the number of response equation iterations is reduced by a factor of 2–3, thereby enabling accelerated MP2 dynamics. Coupled with previously demonstrated Fock matrix extrapolation, the combined iterative SCF and z-vector calculations are reduced to a minority share of the total calculation. Though demonstrated for MP2, these methods can also be generalized to higher levels of electron correlation or excited state methods.