Basis and fit set

With the key BasisDefaults you can control the quality of the basis set, and the level of frozen core approximation. Given your preferences the basis and fit sets are retrieved from the database. The output starts with a copy of your input, but with the basis and fit sets inserted from the database: there you can exactly see what values are used. You can always override the defaults by specifying the AtomType keyword. There is no need for special basis sets for relativistic calculations.