SEARCH Articles Figures Tables Conical intersections phase-change rule Hydrogen molecules phase-change rule Longuet-Higgins phase-change rule Longuet-Higgins phase-change rule conical intersections Longuet-Higgins phase-change rule, loop Longuet-Higgins phase-change rule, loop construction Nuclear dynamics phase-change rule Permutational symmetry phase-change rule Phase changes Phase rule Phase-change rule and Phase-change rule chemical reaction Phase-change rule coordinate properties Phase-change rule loop construction Phase-change rule pericyclic reactions