Table 2. Comparison of the Dispersion Energy in the CCPP2 Approximation with Other Methods for the Helium Dimer, for the Internuclear Separation of 5.6 a0a.
correction | energy |
---|---|
Edisp(20) | –17.067 |
Edisp(2)(TDHF) | –20.924 |
Edisp(2)(2) | –21.354 |
Edisp(2)(CCD+ST(CCD)) | –21.816 |
Edisp(2)(FCI) | –22.278 |
Edisp(2)(CCPP2(T)) | –21.903 |
The energy unit is Kelvin (1 hartree = 315775.02 K).