Below threshold multiphoton dissociation

References [50, 51] contain a number of results from these nonperturba-tive calculations. One of them is the prediction, in a quantitative way, of the process of below threshold multiphoton dissociation, which reflects the fact that, for the volcanic molecules, the vibrational states are essentially unstable states (resonances), e.g.. Refs. [13, 64], due to tunneling. This means that their energies must be written as complex numbers, — r , where the tunneling rate T is obtainable either from semiclassical formulae [64] or from more sophisticated theories [13]. 

C.A. Nicolaides, Th. Mercouris, l.D. Petsalakis, Above and below threshold multiphoton dissociation of volcanic ground states. Application to BeH++, Chem. Phys. Letts. 212 (1993) 685. 

By forming ion-rare gas atom (Rg) complexes, the dissociation threshold of the system is lowered, generally below the photon energy and these predissociation spectra directly reflect the linear absorption spectrum. This technique has also been used to great effect in anion spectroscopy experiments [13]. The multiphoton dissociation approach remains attractive for systems in which the perturbation of the messenger atom carmot be neglected, or in instruments where rare gas attachment is difficult. 

Time-dependent multiphoton dissociation above and below the threshold of diatomic volcanic states [50, 51]... 

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