Long‐range interactions between atoms and molecules

The refractive index data for various gases are fitted to analytical formulae from which may be calculated the coefficient of the leading term of the long‐range two‐body interactions and the coefficient of the leading term of the long‐range non‐additive three‐body interactions. Coefficients are obtained for mixtures of the gases He, Ne, A, Kr, Xe, H 2 , N 2 and CH 4 , the probable error being 5%.