Calculation Of First-order Properties
Computation of first-order properties is requested via
and enables calculation of various one-electron properties such as dipole moment, quadrupole moment, octopole moment, electric field gradients, relativistic corrections (MVD1 approximation), and in the case of open-shell systems spin densities. In addition, a Mulliken population analysis using the corresponding density-matrix is carried out.
At the CC level, first-order properties can be either computed with orbital relaxation included (default option and usually recommended) or with orbital relaxation excluded (requested via DIFF_TYPE=UNRELAXED, consistent with the CC response theory treatment of higher order (frequency-dependent) properties).