J.C. Lehmann

Optical Pumping of Molecules

Publisher Summary This chapter focuses on the concept of optical pumping of molecules. Optical pumping of molecules allows a great number of important molecular parameters to be measured. The most often investigated are: lifetime of the molecular excited state; collision cross-sections for quenching and depolarization; and Lande factors and also fine structure, λ or ρ doubling, hyperfine structure, chemical shifts, spectroscopic constants, and electric dipole moment. Optical pumping can be used for the measurements of molecular parameters, which can be of great help in the analysis of perturbations among electronically excited states. Optical pumping is especially well adapted to the study of the angular aspect of predissociations and other dynamical effects. For example, photodissociation, using polarized light may produce an alignment of the remaining molecules. The technique can also be used for the relaxation of electronically excited molecules. Because the lifetimes in the excited states are generally very short, very fast relaxation processes that would be difficult to observe in the ground state can be investigated. Among these processes, the disorientation of molecule, that is, relaxation among MJ sublevels is of special interest.

Two unexpected effects concerning perturbations of the B3Π0u+ state of molecular iodine

Abstract We present in this paper two new effects observed in the B 3 Π 0 u + state of molecular iodine: a very high diamagnetic correction in the vibrational level υ ′ = 62 and an important orientation of the optically excited molecules due to predissociation. Both effects can be interpreted by taking into consideration the perturbation of the B state by other electronic states.

Assignment of the transitions induced in molecular iodine vapour by a krypton ion laser

Abstract A study of the fluorescence spectra excited in iodine vapour by the lines 5208, 5309, 5682 and 6471 A of a krypton ion laser, gives us the rotational and vibrational quantum numbers of the B 3 Π 0 + u levels excited by these lines.

Anomalous behaviour of the Landé factors and the chemical shift close to the dissociation limit of the B state of molecular iodine

Abstract Resonances in a modulated light beam have been observed on five transitions in the visible band system of I 2 . Lande factors g J and chemical shifts g 1 have been measured for levels very close to the dissociation limit of the B state.