Journal of Chemical Physics, Vol.118, No.14, 6260-6263, 2003
Deficiencies of the bend symmetry coordinates used for methane
We demonstrate that the bend symmetry coordinates commonly used for methane do not determine the shape of the molecule. We suggest a rule that does enable one to associate a unique shape with a set of symmetry coordinates. However, any such rule entails excluding shapes and therefore cannot be used to calculate high-lying levels. (C) 2003 American Institute of Physics.