C6 dipole-dipole dispersion coefficients for the n-alkanes: Test of an additivity procedure

We report on calculations of the dipole-dipole dispersion coefficients for pairs of n -alkane molecules. The results are based on first-principles calculations of the molecular polarizabilities with a purely imaginary frequency argument and which were reported by us in a previous work [P. Norman, A. Jiemchooroj, and Bo E. Sernelius, J. Chem. Phys. 118, 9167 (2003)]. The results for the static polarizabilities and dispersion coefficients are compared to simple algebraic expressions in terms of the number of CC and CH bonds in the two weakly interacting species. The bond additivity procedure is shown to perform well in the present case, and bond polarizabilities of 4.256 and 3.964 a.u . are proposed for the CH and the CC bond, respectively.Original Publication:Auayporn Jiemchooroj, Bo E. Sernelius and Patrick Norman, C6 dipole-dipole dispersion coefficients for the n-alkanes: Test of an additivity procedure, 2004, Physical Review A, (69), 44701, 44701.http://dx.doi.org/10.1103/PhysRevA.69.044701Copyright: American Physical Society http://www.aps.org