The third-order expression for the dispersion interaction between two atoms is written as a sum over lists of transition matrix elements. Particular attention is given to the C9/R9 interaction which occurs in the homonuclear case when one atom is in an S state and the other is in a P state. Numerical values of the C9 coefficient are given for the homonuclear alkali-metal dimers. The size of the C9:C3 dispersion coefficient ratio increases for the heavier alkali-metal atoms. The C11 and C13 coefficients between two helium atoms and lithium atoms in their ground states are also given.
|Number of pages||9|
|Journal||Physical Review A - Atomic, Molecular, and Optical Physics|
|Publication status||Published - 4 Nov 2011|
Tang, L-Y., Yan, Z-C., Shi, T-Y., & Mitroy, J. (2011). Third-order perturbation theory for van der Waals interaction coefficients. Physical Review A - Atomic, Molecular, and Optical Physics, 84(5), 1-9. . https://doi.org/10.1103/PhysRevA.84.052502