Interaction Potential between He and H2

Abstract

The interaction potential of He with H₂ has been determined in the Hartree—Fock approximation. An analytic expression for the interaction potential has been determined in a form suitable for consideration of energy‐transfer problems. The expression is V(X, R, θ)=C exp{‐α₀X+α₁Xr} {A(θ)+B(θ)r}, which is valid for 0≤R≤2 a.u., 2.5≤X≤3.8 a.u., where R=r+R_e, R_e=1.4 a.u. and C=198.378 eV, α₀=1.86176 a.u.⁻¹, α₁=0.3206 a.u.⁻², A(θ)=1.10041 {1+0.18250 P₂(cosθ)}, B(θ)=−0.52151 {1−0.27506 P₂(cos(θ)} a.u.⁻¹. X is the distance between the He and H₂ centers of charge, R is the H₂ bond distance, and XR cosθ=X·R. From this result we see that the force exerted on the oscillator is comparable for both a collision along the line of centers and one along the molecular bisector.