Prolate-oblate oscillation between the ground states of even-even ...

sphericalGeometric collective model (GCM) - A. Bohr (1952)V(,) = A 2 + B 3 cos 3 + C 4 ,(C>0)B0A = A 1 = 0: spinodal pointoblate(=/3)critical-softprolateA 1spinodal0(=0)phase coexistanceA 2A = A c = B 2 /(4C): critical pointVA0 A c( = /3) ( = 0)A = A 2 = 9B 2 /(32C): antisinodal pointA = A c (B 0) and A < 0 (B = 0): first-order phase transition linesA = B = 0: second-order phase transition point (triple-point)