Production of the NaHg Molecule by Reactive Three-Body Collisions following Energy-Transferring Processes of Laser-Excited Na(3 ²P) Atoms

Abstract

We report on the production of the NaHg molecule Via resonant excitation of the sodium D-lines following energy-pooling collisions of laser-excited Na(3 2 P) atoms. In addition to the chemiluminescence on the red NaHg(II 1/2 -X 1/2 ) band system, we observed emission on the blue-band system. Production mechanisms as well as the dependence on particle density and excitation laser intensity are discussed, and the rate coefficients are determined.

Production Rates of Photochemical Reactions by Pulsed Laser Excitation on the Example of the NaHg Molecule

“…In order to account for the background due to Na 2 fluorescence, we also measure the time evolution at 685.5 and 478.0 nm. This spectral positions are known to be free of any NaHg fluorescence, since the NaHg red bands terminate at about 670 nm and the blue bands at about 475 nm. , The background time curves then simply are subtracted from the NaHg signal. It is found that all time evolutions of the red II 1/2 − X 1/2 bands differ only marginally among each other as do the results for the blue III 1/2 − X 1/2 bands.…”

“… for Na and Na 2 and those of ref for Hg, we are able to determine the particle densities n Na 2 and n Hg for each set of heat pipe temperature and buffer gas pressure. Since the particle density of Hg always is about 3 orders of magnitude larger than those of Na 2 , we regard it to be constant in time …”

“…The experimental setup used throughout these experiments is nearly identical to those reported previously. 1 The Na + Na 2 + Hg vapor mixture is prepared in a stainless steel crossed heat pipe oven terminated by four quartz windows. Argon is used as the buffer gas.…”

“…Although thorough investigations of the NaHg molecule have been published previously (see ref and references therein), not very much is known about the lifetimes of its electronically excited states and the production rates of common photochemical reactions leading to production of such molecules. This for sure is due to the fact that the NaHg molecule has only a very shallow ground state with a dissociation energy of about 430 cm -1 .…”

“…On the other hand, we recently reported on production of the electronically excited NaHg(III 1/2 , II 3/2 ) by a reactive threebody collision following energy-pooling collisions of laser excited Na(3 2 P). 1 Although we investigated the time behavior of the NaHg bands, by the complex kinetics of this processes it was not possible to find the lifetimes of the NaHg(III 1/2 , II 3/2 ) states.…”