Electronic-energy exchange cross sections for Ar* (3P) and Kr(1S)

Abstract

Differential cross sections for Ar* scattered by Kr are obtained at four relative kinetic energies, 60.6–156 meV. Location and shape of rainbow maxima, observed at all the energies, are used to determine parameters for a double-Lennard-Jones potential. The parameters, ε=9.11±0.25 meV and rm=5.06±0.84 Å, are the same as those for K+Kr and are substantially different from those of Ar+Kr. A second set of maxima, visible at all energies and caused by exchange of electronic energy from Ar* to Kr, are analyzed to determine electronic-energy exchange cross sections. The cross sections together with those obtained from thermal-energy quenching measurements are consistent with an increase from a threshold of 25 meV. Possible mechanisms for the electronic-energy exchange are discussed.

Analysis of the mass-resolved two-photon spectra of jet-cooled ArKr near Kr*(5p) and Ar*(4s)

“…An overview of the ͑2ϩ1͒ REMPI/TOF spectrum of 40 Ar 84 Kr recorded with linearly polarized UV light is shown in Fig. 2͑a͒.…”

“…19 Since the natural abundance of 40 Ar however, is 99.6% ͑compared to 0.337% for 36 Ar and 0.063% for 38 Ar͒ only the six 40 Isotopic transition wave numbers i for each band system were averaged from a minimum of two separate spectra ͑and often times, many more than two͒ and fitted by the method of least-squares to a mass-reduced Dunham expansion of the form ͑in cm Ϫ1 ͒:…”

“…[20][21][22] Recently, pure rotational spectra for several isotopomers of ArKr were reported by Xu et al 23 The microwave data could be reproduced when the dissociation energy of the ground state and the equilibrium internuclear bond length were adjusted to be D e Љ ϭ 115.476 50 cm Ϫ1 and r e Љ ϭ 3.893 817 75 Å, respectively. Values of e Љ and e x e Љ for the 40 Ar 84 Kr isotopomerϭ26.748 and 1.549 cm Ϫ1 , respectively, were estimated by substituting the Morse dissociation energy formula:…”

“…Overview ͑2ϩ1͒ REMPI/TOF spectra for the 40 Ar 84 Kr isotopomer in the region of the ArϩKr*(5p) and Ar*(4s)ϩKr asymptotes. ͑a͒ Spectrum obtained by linearly polarized two-photon excitation.…”

“…3. The ͑2ϩ1͒ REMPI/TOF spectrum in region I for the 40 Ar 84 Kr isotopomer which is assigned to a 2←0 ϩ transition. The strong negative peak is a baseline distortion caused by exciting the Kr* 5 p͓5/2͔ 2 ←Kr͑ 1 S 0 ͒ twophoton resonance.…”