14644-45-2Relevant articles and documents
Laser spectroscopy and dynamics of the jet-cooled AsH2 free radical
He, Sheng-Gui,Clouthier, Dennis J.
, p. 1 - 9 (2009/02/02)
The A2A1-X2B1 electronic transition of the jet-cooled AsH2 free radical has been studied by laser-induced fluorescence (LIF), wavelength-resolved emission, and fluorescence lifetime measurements. The radical was produced by a pulsed electric discharge through a mixture of arsine (AsH3) and high pressure argon at the exit of a pulsed valve. Nine vibronic bands wereidentified by LIF spectroscopy in the 505-400 nm region, including a lo ng progression in the bending mode and two bands (101 and 101201) involving the excited state As-H symmetric stretch. Single vibronic level emission spectra showed similar activity in the bending and symmetric stretching frequencies of the ground state. High-resolution spectra of the 000 band exhibited large spin splittings and small, resolved arsenic hyperfine splittings, due to a substantial Fermi contact interaction in the excited state. The rotational constants obtained in the analysis gave effective molecular structures of r″0 = 1.5183(1) ?, θ″0=90.75(1) ° and r′0=1.4830(1) ?, θ′0= 123.10(2)°. The excited state fluorescence lifetimes vary dramatically with rovibronicstate, from a single value of 1.4 μs to many with lifetimes less tha n 10 ns, behavior which the authors interpret as signaling the onset of a predissociative process near the zero-point level of the ground state.
