Pendular states of highly vibrationally excited molecules

The behavior of coherent field-induced hybrids of held-free rotor states (" pendular states") is studied in energy regions where intramolecular vibrati onal energy redistribution phenomena are important. The energy region corre sponding to the 4v(1) band system of HCCF molecules, at approximately 12 80 0 cm(-1) has been chosen as an example. The calculations show that the expe ctation value of the orientation of molecules prepared in nonstationary: pe ndular bright states exhibits a slow decay to the equilibrium value. Theref ore the molecules substantially conserve their initial orientation after in tramolecular vibrational redistribution takes place. [S0031-9007(99)08810-9 ].