This adds orbitals orb1.sym1 to orb2.sym2 to the output vectors, starting at orb3.sym3. The input vectors are scaled by the factor fac. If fac=0, fac is set to 1.0. For other details see MOVE command. Note, however, that the output vectors which have already been defined are not skipped as for MOVE.
See also MOVE and EXTRA commands.