Abstract

The collisional deactivation of electronic, vibrational, and rotational states of GeF was studied using laser-induced fluorescence (LiF). Interest in this molecule was stimulated by the work of S. Davis who pointed out the potential of group IVA fluorides as chemical laser candidates due to large ground state splitting. Experimentally, Ge vapor evaporated by a pulsed YAG laser was reacted with F2, dilute in He, to form GeF. Pulses from a dye laser (~10 mJ, 12 ns) pumped the GeF to a specific vibrational-rotational level of the A²∑ electronic state. By scanning the laser wavelength LIF spectra were produced. Temporal decay of the fluorescence from a single excited level was used to determine relaxation rates as radiative lifetime = 1 × 10⁶ s; V–V transfer = 1.6 × 10⁵ s⁻¹ Torr⁻¹; rotational relaxation = 1 × 10⁷ s⁻¹ Torr⁻¹. By saturating the pumped level and comparing the LIF to chemiluminescence the population ratio in A/X states at V = 0 was found approximately as 1/7. The formation and loss of GeF(X) was followed by observing LIF intensity as the dye laser pulse was delayed past the YAG evaporation pulse. Also, the temporal concentration changes of GeF(A) followed from chemiluminescence intensity. The results are compared to a simple kinetic model which incorporates reaction and deactivation rates.

© 1986 Optical Society of America