The format for the user–defined basis section is as follows:
$basis 0 **** $end
where Atomic symbol of the atom (atomic number not accepted) Angular momentum symbol (S, P, SP, D, F, G) Degree of contraction of the shell (integer) Scaling to be applied to exponents (default is 1.00) Gaussian primitive exponent (positive real number) Contraction coefficient for each angular momentum (non–zero real numbers).
Atoms are terminated with **** and the complete basis set is terminated with the $end keyword terminator. No blank lines can be incorporated within the general basis set input. Note that more than one contraction coefficient per line is one required for compound shells like SP. As with all Q-Chem input deck information, all input is case–insensitive.