Determination of the Lennard-Jones Parameters from Second Virial Coefficients Tabulation of the Second Virial Coefficient

Values of B/(2πNσ3/3) to four decimal places as a function of θ/T are computed from θ/T=0.20 to 1.00 for a Lennard-Jones (6, 12) potential. The equation B/(2πNσ3/3) = (θ/T)¼[1.064–3.602(θ/T)] computes the tabulated values fairly well. Thus σ and θ can be determined from experimental B values by plotting BT¼ against 1/T and finding the slope and intercept of the best straight line through the points. For methane and n-butane this method gave parameters that computed B values agreeing with observed values within the experimental uncertainty.