Ionela Ionescu

On the energy dependence of the Zeeman and hyperfine parameters in the state of OH and OD

Abstract We report quantum beat studies of the energy dependence of the Zeeman parameters in the A 2 Σ + state of OH and OD, and the nuclear hyperfine parameters of OD( A 2 Σ + ). In contrast to previous work, we find that the sign and magnitude of the anisotropic g-factor gl for υ′=0 is consistent with that expected from Curl’s relationship. However, at higher energies gl changes sign, a result we attribute to interaction with the repulsive 1 4 Π state, which is known to lead to predissociation at higher energies. The magnetic and electric quadrupole hyperfine constants were determined for OD( A 2 Σ + ,υ ′ =0–3) , and the constants for υ′=2,3 are reported here for the first time. The derived values are consistent with previous experimental results and available ab initio calculations.

Fluorescence spectra of NH2 X̃ 2B1←Ã 2A1 Σ bands: Experiment and theory

We report new calculations and measurements of fluorescence properties of the title system, which is important in astrochemical processes. Dispersed fluorescence spectra show extensive X 2B1 vibrational progressions that depend on the initial A 2A1 state. Observed and calculated (0,ν2′,0)Σ lifetimes are in good accord, save for ν2′=4 (bent molecule notation), and calculated (1,ν2′−2,0)Σ lifetimes are longer than the (0,ν2′,0)Σ ones. The calculated laser-induced fluorescence spectrum is compared with experimental absorption data and with previous calculations, finding that the present treatment underestimates the intensity of the (0,4,0)Σ band.