Collisional effects on angular momentum orientation in acetylene X̃ 1Σg+ (ν2″=1,j″). II. Disorientation by rotationally elastic and multiple inelastic collisions

Abstract

Fate of isolated CH (B 2 Σ − ,v=0,J) states in inelastic collisions with CO

Elastic depolarization and polarization transfer in CN(A2Π,v= 4)+Ar collisions

“…[39][40][41] The alignment retention they observed was very similar to that reported here, averaging 40% for a range of ∆j = ±2 transitions studied. 39 The simplest models to fit these polarization ratios are ones in which limited ranges of either ∆m j or classical tilt angle, ' jj θ , are allowed.…”

“…We also observe a significant [39][40][41] The orientation and alignment elastic depolarization rates were both measured, and found to be essentially equal, and to decline with increasing j. The similar orientation and alignment rate constants are inconsistent with any simple model in which the magnitude of ∆m j in a single collision is restricted, as these will lead to destruction of alignment faster than orientation.…”

“…[36][37][38] There are fewer more recent experimental studies of other species. Notable exceptions are the work of Rudert et al, who studied elastic depolarization and polarization transfer of both orientation and alignment in C 2 H 2 self-collisions, [39][40][41] and the measurement of alignment transfer in self-collisions of N 2 by Sitz and Farrow. 42,43 Further discussion of these experiments is deferred until later in this paper, but we note that these systems differ in being closed shell and therefore proceeding on single…”

Spectroscopy and energetics of the acetylene molecule: dynamical complexity alongside structural simplicity

“…More comprehensive UV-scanned Raman-UV DR spectroscopic studies of this type have been performed by Zacharias and coworkers [161,162,167], examining the RET propensities for even-ÁJ population changes and fitting the associated rate constants to a model based on the energy-corrected sudden approximation and a power-gap scaling law. Zacharias and coworkers have extended their Raman-UV DR experiments investigations to investigate M J -changing self-collisions in C 2 H 2 gas, together with a microscopic model for the resulting effects on molecular alignment and orientation [168][169][170].…”

“…Double-resonance schemes using tunable lasers to monitor coherent Raman excitation of specific molecular rovibrational states were first reported in 1983, with two variants based, respectively, on detection by LIF in D 2 CO vapour [322] and multiphoton ionization (MPI) in NO gas [323]. Subsequent early LIF-detected Raman-UV DR experiments studied glyoxal (C 2 H 2 O 2 ) [324,325], H 2 and D 2 [326], C 2 H 2 [50,52,53,54,57,161,162,[167][168][169][170], C 2 HD and C 2 D 2 [52], and stilbene [327]. Corresponding early MPI-detected Raman-UV DR experiments examined H 2 [328][329][330], benzene and other aromatics [331][332][333][334][335], HCl [336], and N 2 [337].…”