CORRELATION DIAGRAMS FOR RIGID AND NONRIGID 4-BODY SYSTEMS

Correlation diagrams are constructed to connect the rotation-vibration energy levels of idealized limiting models for the tetratomic molecule. One limit is the completely nonrigid homonuclear four-atom cluster. Several choices are taken for the other limit: the nearly rigid regular tetrahedron and square, the dimer of two identical homonuclear diatomics, and the ammonialike inverter. A dimensionless parameter, the ratio of two energies, is proposed to characterize the degree of nonrigidity for molecules of arbitrary size or complexity. The parameter is evaluated for several examples. © 1979 American Institute of Physics.