“…There is a series of other JTE and PJTE problems (some of them considered below in this review), with many applications to studies of molecular and solid state phenomena, reflected in original publications, reviews, and books cited in the introduction, notably refs , , , and − for books, refs , , , and − for major reviews, and refs − for more recent developments of the vibronic coupling theory in relation to the JTE and PJTE. In addition to the noted above E⊗e problem of systems with 2-fold degenerate states, widespread are also problems T⊗ e , T⊗ t 2 , T⊗( e+t 2 ) of cubic systems with 3-fold degenerate T terms interacting with e and t 2 displacements, and higher level of degeneracy in icosahedral systems, as well as combined and multimode JTE problems <...…”