Low‐Temperature, Low‐Pressure Transport Coefficients for Gaseous Oxygen and Sulfur Atoms

The transport properties of a gas at low temperature can be estimated in terms of the potential energy curves at very large separations. For this purpose it is only necessary to know the dispersion and multipole energies of interaction. Such calculations are carried out for the interaction of two oxygen or two sulfur atoms in their ground states. The atoms have an a priori probability pi of interacting in accordance with one of a set of potential energy functions Φi(R), where pi is proportional to the sum of the degeneracies of the states of the collision complex to which Φi(R) applies. For such collisional problems involving more than one potential energy function, the collision cross section Q for any process is rigorously additive in the sense that Q = ΣipiQi, where Qi is the collision cross section considering only the ith potential.