Intramolecular dependence of the frequency-dependent polarizabilities of K 2(a 3Σ u+) and van der Waals dispersion coefficients for X+K 2, X 2+K and X 2+K 2 (X=Li,Na,K)

Abstract

The ab initio time-dependent gauge-invariant method has been used to compute the frequency-dependent dipole polarizabilities of the first triplet state of K 2(a 3Σ u +), and to study its dependence on the internuclear distance. Then, isotropic C 6 000 and anisotropic C 6 202 long-range coefficients of X( 2S)+K 2(a 3Σ u +), K( 2S)+X 2(a 3Σ u +) and X 2(a 3Σ u +)+K 2(a 3Σ u +) (X=Li,Na,K) have been evaluated using dynamic dipole polarizability values of K and K 2. From the determination of the dynamic quadrupole polarizability components of both interacting species, C 8 000, C 8 202 and C 8 404 have been also obtained for the X( 2S)+K 2(a 3Σ u +) and K( 2S)+X 2(a 3Σ u +) (X=Li,Na,K) interacting systems at the calculated equilibrium distance of K 2 (11.57 bohr), as well as the three-body C 9 long-range coefficients depending only on the dipole polarizability of K. Good agreement with the previous values of Marinescu and Starace [Phys. Rev. A 55 (1997) 2067] is obtained for these last coefficients.