BSSE Corrected Interaction Energies

As emphasized several times, interaction energies need to be corrected for the effect of using incomplete basis sets. When the full CP correction is used, the corrected interaction energy is defined as follows  

The input file for GAMESS is not as simple. One has to prepare and carry out three calculations. First, one performs the full optimization using the chosen basis sets. Then one must prepare an input file with the optimized geometry and use a nuclear charge of zero to eliminate nuclei and electrons on one of the monomers. Similarly, another input file must be prepared for the second mono- 

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TABLE 6.3. BSSE-Corrected Interaction Energies and H- -H Distances for Li and Na Dihydrogen-Bonded Complexes Formed with Various Proton-Donor Molecules ... 

The first high-level theoretical evidence for the existence of dihydrogen bonds between CH4 and [NH4]+ came in 1996 [5]. In the sense of bonding geometry, this complex is not linear (Structure 6.5), has Csv symmetry, and exhibits three relatively short H- -H contacts with distances of 2.237, 2.357, and 2.226 A calculated at the RHF/6-31G, RHF/6-311++G, and MP2/6-31G lev-els, respectively. According to the frequency analysis at the RHF/6-31G level, the complex occupies a minimum on the potential energy surface of this system. The BSSE-corrected interaction energies have been calculated as —2.46,... 

BSSE corrected interaction energies (kcal/mol) of D-FA, D-MFA and K-DMSO systems calculated at the B3LYP/3-21G level of the theory, and using ONIOM(B3LYP/3-21G PM3) method [148,149] ... 

Let us first analyze the results of the calculations of geometrical parameters. The most important outcome of these investigations could be summarized as follows (see Table 5, which presents BSSE corrected interaction energies of TNB adsorption on the siloxane surface) [197,198],... 

BSSE corrected interaction energy (kcal/mol) of TNB adsorption on the siloxane surface and distances (A) between the TNB plane and the siloxane surface calculated at the HF and DFT level of theory and using the ONIOM method [197, 1981 ... 

The calculation results of the dipole moment, the OH bond length for the monomers, and the BSSE-corrected interaction energy for the dimers are listed in Table 21.1. Available experimental data are also listed for comparison. 

Table 1. Value of the energetic components of the interaction energy for the indicated systems, computed using the IMPT method. Ea, E, Ep, ct, and (jjsp are, respectively, the electrostatic, exchange-repulsion, polarization, charge-transfer, and dispersion components. tot is the sum of these components and Euvi is the BSSE-corrected interaction energy, shown to serve as reference to calibrate the quality of the IMPT calculation. The MP2 intermolecular optimum distance is also shown (ropt). Distances are given in A and energies in kcal/mol...

Figure 14. Variation of the MP2 BSSE-uncorrected and BSSE-corrected interaction energies of the methane-water complex with the basis set. Circles indicate results obtained using Pople basis set, while squares indicate results obtained with the aug-cc-pVxZ basis sets. The geometry is the optimum one computed at the MP2/aug-cc-pVTZ level.

Calculations run along the same lines as above showed a very long H- O equihbrium distance of 2.56 A and a BSSE-corrected interaction energy of only... 

Table H. BSSE corrected interaction energies (AE ) for the CO2 complexes.

The basis set superposition error (BSSE) corrected interaction energies were estimated using the Boys-Bemardi counterpoise correction scheme. The intouction energy (Em) in the ground state was calculated using the formula ... 

Table 5 Variation of the BSSE Corrected Interaction Energies (A , f, kcal/mol) with Respect to the Size of the Basis Sets...

Fig. 2.20 Extracted symmetry nonequivalent dimers from the crystal packing of a CT4 b C2F4 and c CgFg. Numbers in brown colors represent BSSE corrected interaction energy (in kcal/mol) at MP2/aug-cc-pVDZ level. Reprinted with the permission from Ref. [116]. Copyright 2010 Springer-Verlag...

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