In this work, we calculated the second virial coefficients B2 of monatomic lithium, sodium
and potassium gases by using the most recent ¹Σ⁺_g and ³Σ⁺_u Rydberg-Klein-Rees interatomic potentials. We have also determined the viscosity η and thermal conductivity λ coefficients of the alkali-metal vapors as a function of the temperature T. The results we found of the collision integrals and of the coefficients η and λ agree quite well with some available experimental data.
We have also investigated the variation law with temperature T of the above thermophysical
quantities. For temperatures ranging from 100 to 3000K, the results can be reproduced
by simple formulas
η(T) = AT^α
λ(T) = BT^α
where for T in Kelvin, η in micropoise (1 P = 0.1 Pa·s), and λ in 10^-3 W·m^-1·K^-1 :
• lithium Li: A = 0.314 , B = 0.1398 and α = 0.863;
• sodium Na: A = 0.624, B = 0.0846 and α = 0.827;
• potassium K: A = 0.400, B = 0.0320 and α = 0.883.