A pure-rotational collisionally pumped OH laser

Abstract

Laser oscillation is reported on certain pure-rotational transitions in the ground electronic state of the hydroxyl ion, v=0 and v=1. the active medium has been prepared by the O(1D)+H2 reaction in a large excess of rare gas. The transitions on which oscillation occurs have upper states which are energetically resonant with one, or even two, vibrational quanta. The pumping mechanism is assigned as a V→R transfer with ΔJ the order of 12.

Competitive partitioning of rotational energy in gas ensemble equilibration

“…1, with similar behaviour highlighted recently for OH*. 3,4 The highly inverted rovibrational populations obtained by Pimentel et al 16 for HF and by Robinson and co-workers 17 in the case of OH are readily reproduced by our model and shown to be the result of QVRT. 3 In addition, our model of OH* in N 2 /O 2 was able to reproduce the exceptionally high rotational excitation, n OH > 30, previously identified in Earth's airglow 18 as originating from OH molecules in the mesosphere.…”

“…As a result, direct comparison of our predicted T m evolution with experiment is not possible except in a limited and indirect manner. For example, both HF and OH have been used as the gain media in chemical lasers, 16,17 devices that operate under multi-collision conditions -generally in a buffer of rare gas atoms. These species are formed rovibrationally hot from highly exothermic chemical reactions and laser action is observed from a range of states depending on the extent of exothermicity of the initiating reaction.…”

Test studies on the potential energy surface and rate constant for the OH+O3 atmospheric reaction

“…(8) and (9) in Eq. (4) and performing the integration analytically, yielding 4), while the available experimental data [9], ®tted Arrhenius plots [8,9,29,30], and curve [5] recommended by the IUPAC Subcommittee on Gas Kinetics Data Evaluation for Atmospheric Chemistry are also indicated.…”

“…We have carried out a QCT study of the reaction OH v 0 O 3 3 HO 2 O 2 using a newly developed DMBE potential energy surface for ground-state HO 4 . Although using an empirical calibration of a simple ®ve-body energy term, the calculated k T vs T curve was shown to agree well with the recommended data over the whole range of temperatures, where the calculations and experimental data overlap.…”

“…The hydrogen±oxygen systems play a central role in the chemistry of Earth's atmosphere [1,2], combustion chemistry [3], and laser processes [4]. In particular, the reaction OH O 3 3 HO 2 O 2 1 in¯uences the steady-state concentration of many trace gases which are important in stratospheric chemistry (the enthalpy of reaction is DH 0 À40X01 kcal mol À1 [5]).…”