A review of spin Hamiltonian forms for various point-group site symmetries

A review has been made of the spin Hamiltonian forms for all the 32 point groups, including linear magnetic field-dependent terms in spin operators All spin operators (O) over cap(1)(m), (O) over cap(3)(m), (O) over cap(5)(m), <(Omega)over cap>(m)(1), <(Omega)over cap>(m)(3), and <(Omega)over cap>(m)(5). All spin operators, as well as their matrix elements, to be used in constructing spin Hamiltonian matrices, have been listed. The various point group aggregates for distinct spin-Hamiltonian forms have been classified. In addition, descent of symmetry point groups, useful for studying structural phase transitions, have been indicated.