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Computational Chemistry Software
NWChem 6.0 for Windows
The user manual documentation is also avaiballe in single-file pdf format.
EGView (version 09.07.2011)A convenient tool to analyze results of Gaussian 03/09 BSSE-corrected calculations
How does it work?
BSSE-corrected Stabilization energy SE is obtained asSee also the sample calculation
SE = EA+BDCBS - EADCBS - EBDCBS = EA+BCP - EAMCBS - EBMCBS
where EA+BDCBS is BSSE-uncorrected electron energy, EADCBS is the electron energy of fragment A in a complex obtained using DCBS (Dimer-Centered Basis Set), EBDCBS is the electron energy of fragment B in a complex obtained using DCBS (Dimer-Centered Basis Set), EA+BCP is BSSE-corrected electron energy using counterpoise method:
EA+BCP = EA+BDCBS + ΔEBSSE with the BSSE-correction value ΔEBSSE = EAMCBS - EADCBS + EBMCBS - EBDCBS
Note that ΔEBSSE > 0 sicnce EXDCBS < EXMCBS.
All the values from these equations appear in the Gaussian .out file if the counterpoise keyword is used.
Counterpoise: doing DCBS calculation for fragment 1 NewBq=T ... SCF Done: E(RB+HF-LYP) = -56.5595347922 A.U. after 5 cycles Convg = 0.1804D-08 -V/T = 2.0095 S**2 = 0.0000Here NewBq is a synonym for NewGhost
and DCBS = Dimer centered basis set
Counterpoise: doing DCBS calculation for fragment 2 NewBq=T ... SCF Done: E(RB+HF-LYP) = -114.503484307 A.U. after 6 cycles Convg = 0.3794D-08 -V/T = 2.0090 S**2 = 0.0000EAMCBS
Counterpoise: doing MCBS calculation for fragment 1 ... SCF Done: E(RB+HF-LYP) = -56.5577674045 A.U. after 5 cycles Convg = 0.2728D-08 -V/T = 2.0092 S**2 = 0.0000Here MCBS = monomer-centered basis set
Counterpoise: doing MCBS calculation for fragment 2 ... SCF Done: E(RB+HF-LYP) = -114.503149487 A.U. after 5 cycles Convg = 0.9897D-08 -V/T = 2.0090 S**2 = 0.0000For post-SCF methods keywords such as EUMP2 etc appears after "Counterpoise: doing XXXX calculation for fragment Y"
The following output appears regardless of the energy calculation method used:
Counterpoise: corrected energy = -171.065201221288and the BSSE-correction energy (ΔEBSSE)
Counterpoise: BSSE energy = 0.002102207582
Note that all these values are calculated for fragments geometries as they are in complex, so their deformation energy is not included. This is a good approximation (< 0.1 kcal/mole) only if interacting molecules are rigid enough.
Some open-source QC code referencesThe quantum-chemistry freeware libraries
Updated: Aug 23, 2011
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