TY - JOUR

T1 - Long range C, N and H atom-atom potential parameters from ab initio dispersion energies for different azabenzene dimers

AU - Huiszoon, C.

AU - Mulder, Fred

N1 - Funding Information:
In a previous paper \[1\] we have compared the results from the empirical atom-atom \[2-8\] approach with the long range interactions from ab initio calculations for ethylcne and pyrazine dimers. The agreement for the dispersion energy was striking, whereas the electrostatic interaction showed rather large discrepancies. Rccently several efforts have been made to obtain non-bonded atom-atom potential parameters, concerning both the long and short range interactions, from ab initio calculated intermolecular potentials \[9-18\]. The correctness of the atom-atom model \[9, 10, 12-18\] as well as the transferability \[13, 14, 19\] of the parameters to molecules not included in the fitting procedure have been considered. In a preceding paper \[20\] (referred to as paper I) we have reported on ab initio calculations of the long range interactions of the t Supported in part by the Netherlands Foundation for Chemical Research (SON) with financial aid from the Netherlands Organization for the Advancement of Pure Research (ZWO).

PY - 1979/11

Y1 - 1979/11

N2 - After comparing theoretically the atom-atom model with the multipole expansion for the dispersion energy, we derive atom-atom potential parameters for C, N and H contacts by fitting the atom-atom dispersion energies to the dispersion interactions calculated by an ab initio method for the following (aza)-benzene molecules: benzene, pyridine, pyridazine, pyrimidine, pyrazine, s-triazine and s-tetrazine. The data base for the fit consists of 1200 randomly chosen configurations for each azabenzene dimer. The optimized parameters for the carbon and hydrogen contacts in particular are not unique; reasonably good fits are obtained with different parameter sets. A very simple rule, which relates the atom-atom potentials to the isotropic molecular C6 dispersion coefficients, already leads to good estimates for the parameters. From the empirical parameter sets available in the literature the William- Go vers set yields results which are close to our ab initio dispersion energies.

AB - After comparing theoretically the atom-atom model with the multipole expansion for the dispersion energy, we derive atom-atom potential parameters for C, N and H contacts by fitting the atom-atom dispersion energies to the dispersion interactions calculated by an ab initio method for the following (aza)-benzene molecules: benzene, pyridine, pyridazine, pyrimidine, pyrazine, s-triazine and s-tetrazine. The data base for the fit consists of 1200 randomly chosen configurations for each azabenzene dimer. The optimized parameters for the carbon and hydrogen contacts in particular are not unique; reasonably good fits are obtained with different parameter sets. A very simple rule, which relates the atom-atom potentials to the isotropic molecular C6 dispersion coefficients, already leads to good estimates for the parameters. From the empirical parameter sets available in the literature the William- Go vers set yields results which are close to our ab initio dispersion energies.

UR - http://www.scopus.com/inward/record.url?scp=0001034178&partnerID=8YFLogxK

U2 - 10.1080/00268977900102601

DO - 10.1080/00268977900102601

M3 - Article

AN - SCOPUS:0001034178

VL - 38

SP - 1497

EP - 1506

JO - Molecular physics

JF - Molecular physics

SN - 0026-8976

IS - 5

ER -