 ## Firefly and PC GAMESS-related discussion club

Learn how to ask questions correctly  MP2 - EFP Energy

Rahul Singh
rahulsn@iastate.edu

Hello Everyone,

а а а а а I have been doing simulations in vacuum and in water for a certain molecule. I have modeled the water using EFP and have used MP2 for the ab-intio calculations. Now, when I am comparing the energies of the molecule in water and in vacuum, the difference in energy is very large and comes around ~ 7 hartrees. This large difference has not been reported in previous papers but of course nobody has used MP2-EFP combination. So, please tell me which energy is correct and should be compared with the energy in vacuum. The three options which I see in the log file are :

Energy = Solute potential energy + Solute kinetic energy а а аor
Energy = Total Energy а or
Energy = Total Energy - Effective Fragment Energy

This is how the energy values look like in an MP2-EFP calculation

а а а а а а а аONE ELECTRON ENERGY = а -5521.7840543068
а а а а а а а аTWO ELECTRON ENERGY = а а2405.7150238918
а а а а а NUCLEAR REPULSION ENERGY = а а2049.8047313555
а а а а аEFFECTIVE FRAGMENT ENERGY = а а а-7.6260095839
а а а а а а а а а а а а а а а а а а а------------------
а а а а а а а а а а а TOTAL ENERGY = а -1073.8903086434

ELECTRON-ELECTRON POTENTIAL ENERGY = а а2405.7150238918
аNUCLEUS-ELECTRON POTENTIAL ENERGY = а -6587.0748922130
а NUCLEUS-NUCLEUS POTENTIAL ENERGY = а а2049.8047313555
ELECTRON-FRAGMENT MULTIPOLE ENERGY = а а а 0.4295428235
ELECTRON-FRAGMENT REMAINDER ENERGY = а а а-0.0600891940
а а а аSTATIC INTERFRAGMENT ENERGY = а а а-5.1078075649
а а а а а аFRAGMENT-NUCLEAR ENERGY = а а а-0.4524465268
а аTOTAL FRAGMENT INDUCTION ENERGY = а а а-2.0717456091
а а а а а а а а а а а а а а а а а а а------------------
а а а а а а TOTAL POTENTIAL ENERGY = а -2138.8176830370
а а а а а а а а а а а а а а а а а а а------------------
а а а а а аSOLUTE POTENTIAL ENERGY = а -2131.5551369657
а а а а а а аSOLUTE KINETIC ENERGY = а а1064.9273743936
а а а а а а а а VIRIAL RATIO (V/T) = а а а 2.0015967175   Tue Apr 15 '14 9:16pm   This message read 602 times