Lawrence Berkeley National Laboratory
Scaled Opposite Spin Second Order Moller-Plesset Correlation Energy: An Economical
Electronic Structure Method
- Author(s): Jung, Yousung
- Lochan, Rohini C.
- Dutoi, Anthony D.
- Head-Gordon, Martin
- et al.
A simplified approach to treating the electron correlation energy is suggested in which only the alpha-beta component of the second order Moller-Plesset energy is evaluated, and then scaled by an empirical factor which is suggested to be 1.3. This scaled opposite spin second order energy (SOS-MP@) yields results for relative energies and derivative properties that are statistically improved over the conventional MP2 method. Furthermore, the SOS-MP2 energy can be evaluated without the 5th order computational steps associated with MP2 theory, even without exploiting any spatial locality. A 4th order algorithm is given for evaluating the opposite spin MP2 energy using auxiliary basis expansions, and a Laplace aproach, and timing comparisons are given.