Upper and lower bounds of two- and three-body dipole, quadrupole, and octupole van der Waals coefficients for hydrogen, noble gas, and alkali atom interactions

Abstract

Upper and lower bounds of the multipole van der Waals coefficients C6, C8, and C10 for hydrogen, noble gas, and alkali atoms are established. Nonadditive three-body coefficients involving dipole, quadrupole, and octupole interactions are also determined. For the dipole polarizabilities a three-term, two-point Padé approximant is used to obtain the upper bound and a two-term Padé approximant is used to obtain the lower bound. For the quadrupole and octupole polarizabilities a one-term approximation of the dynamic polarizability is used, except for the helium quadrupole polarizability, where extended approximations are possible.