The following example shows various uses of the MATROP commands.
This second example adds a quadrupole field to H0. The result is exactly the same as using the QUAD command. H0 is overwritten by the modified one-electron matrix, and the nuclear energy is automatically changed appropriately. The subsequent SCF calculations use the modified one-electron operator.
Note that it is usually recommended to add fields with the DIP, QUAD, or FIELD commands.