Effect of Debye plasmas on the dispersion coefficients $C_8$, $C_{10}$, and $C_{12}$ for interactions between atoms has been investigated using highly accurate correlated exponential basis functions. In the free-atom case, the dispersion $C_{12}$ coefficient and the hexadecapole polarizability for helium are reported. The dispersion coefficients, hexadecapole polarizability, and $1s5g$ ${}^1{G}^e$ state energy of helium for different screening parameters are also reported.

• Received 31 March 2010

DOI:https://doi.org/10.1103/PhysRevA.81.062506