Thomas-Fermi fields for molecules with tetrahedral and octahedral symmetry

Abstract

Abstract The Thomas-Fermi method has been applied to molecules with tetrahedral or octahedral symmetry in the approximation in which the nuclei of the outer atoms are smeared out over the surface of a sphere. Solutions are given for the molecules CH 4 , CF 4 , CCl 4 , SiH 4 , SiF 4 and SF 6 , and using the results presented here it will not be a difficult matter to obtain the solutions for other molecules if they should be required. A comparison of the results for CH 4 with those of Buckingham, Massey and Tibbs shows that whilst for such a light molecule the charge distribution is somewhat poor, the potential is already in good agreement with the results of the Hartree self-consistent field method. For CCl 4 , however, the approximation of smoothing out all the protons appears to break down. An alternative approximation in which the K and L shell electrons are compressed into the nucleus and the modified nuclear charges smoothed, has been investigated and appears to give more reasonable results. A discussion of the energy has been given, but the method is not sufficiently accurate to be of value for energetic considerations.