modifying (tuncating) basis sets?
I want to use the LANL2DZ for Cu(2+). Now, this basis set contains some
diffuse functions which should be unnecessary for a cation. Some publications
mention such truncated basis sets and some people in our lab also used to
truncate basis sets.
Well, I'm a little bit suspicious about such modifications. Should such
modifications be done, i.e. is it safe? When should a function be considered
as diffuse? (LANL2DZ for instance has three uncontracted (1 x s, 2 x p)
functions with exponents that "look" small.) What about truncations