Control of collisionless and collisional processes by nonresonant laser fields

Journal Article · Fri Apr 01 04:00:00 EST 1977 · Phys. Rev., A; (United States)

DOI:https://doi.org/10.1103/PhysRevA.15.1570· OSTI ID:7323636

Lau, A M.F.; Rhodes, C K

The presence of coherent radiation fields can modify various atomic, ionic, and molecular processes. Cases were examined where the changes can be effected without actual absorption or emission of photons. The radiation fields cause optical Stark shifts of the energies and dress the nonadiabatic couplings between states. Rates of processes such as dissociation, predissociation, atomic and molecular collisions can be radiatively controlled. Formation of new avoided crossings due to radiative interaction gives rise to new phenomena. B exact numerical results from which the influences of the radiation field on arbitrary configurations can be calculated, and simple but accurate analytic results, from which these effects can be conveniently assessed are given. It is shown that the inelastic transition probability is decreased at a true crossing and is increased at an avoided crossing as a result of the presence of the nonresonant radiation field. Furthermore, for two parallel levels with constant nonadiabatic coupling, it is shown that the amplitudes of the nonadiabatic transition are invariant, but its flopping frequency is reduced by the field. Depending on the kinds of final measurements with the field on or off, general behaviors of the inelastic transition probability as a function of the field parameters and the charge-system parameters are predicted and the possibility of inversion (from a field-free value of less than 1/2 to a value greater than 1/2) is demonstrated. Experimental investigation with iodine molecules is suggested. Comparison of nonperturbative results with those of stationary perturbation theory shows that the latter is inadequate in an important parameter region where the field modification of processes is greater than 1%.

• Research Organization: Molecular Physics Center, Stanford Research Institute, Menlo Park, California 94025
• OSTI ID: 7323636
• Journal Information: Phys. Rev., A; (United States), Journal Name: Phys. Rev., A; (United States) Vol. 15:4; ISSN PLRAA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400203* -- Isotope Exchange & Isotope Separation-- (-1987)
ATOM COLLISIONS
CHEMICAL REACTIONS
COLLISIONS
ELECTROMAGNETIC FIELDS
ELECTROMAGNETIC RADIATION
ENERGY LEVELS
EXCITED STATES
ISOTOPE SEPARATION
LASER ISOTOPE SEPARATION
LASER RADIATION
MOLECULE COLLISIONS
RADIATIONS
SEPARATION PROCESSES