Hi all,
I wanted to investigate the interactions between charged groups with SAPT. I followed the input from the manual. The output showed very large values for electrostatics (-118.19630204 kcal/mol). I’m not too sure if this makes physical sense. I minimised my structures first with MP2 and a double zeta basis set. Can anyone shed some light on why I am getting these values?
Thanks in advance,
Eric
Input
molecule arg_carb {
1 1
N 2.871509 0.425563 -0.032645
C 1.544924 0.290062 -0.085864
N 0.971332 -0.894907 0.114337
N 0.766447 1.346429 -0.360572
C 3.781042 -0.679543 0.207392
H 3.252449 1.359164 -0.140984
H 3.701853 -1.438759 -0.580422
H 3.592498 -1.147313 1.181541
H 4.798827 -0.286649 0.204851
H 1.18766 2.268526 -0.326197
H -0.236255 1.274701 -0.118454
H 1.538184 -1.72862 0.208982
H -0.040825 -0.9988 -0.075165
--
-1 1
O -1.814201 -1.04752 -0.474678
O -1.962211 0.994214 0.431762
C -2.478162 -0.08179 0.006249
C -3.977669 -0.229866 0.113582
H -4.361611 -0.983381 -0.582074
H -4.482006 0.727497 -0.05895
H -4.225293 -0.552688 1.134205
units angstrom
}
set globals {
basis aug-cc-pvdz
guess sad
scf_type df
}
set sapt {
print 1
nat_orbs_t2 true
freeze_core true
aio_cphf true
aio_df_ints true
}
energy('sapt2+3')
Output
Special recipe for scaled SAPT0 (see Manual):
Electrostatics sSAPT0 -188.35778907 [mEh] -118.19630204 [kcal/mol] -494.53337521 [kJ/mol]
Exchange sSAPT0 44.07183788 [mEh] 27.65549695 [kcal/mol] 115.71061035 [kJ/mol]
Induction sSAPT0 -36.27183851 [mEh] -22.76092325 [kcal/mol] -95.23171200 [kJ/mol]
Dispersion sSAPT0 -11.32677616 [mEh] -7.10765964 [kcal/mol] -29.73845080 [kJ/mol]
Total sSAPT0 -191.88456586 [mEh] -120.40938798 [kcal/mol] -503.79292767 [kJ/mol]