Comment on Dennis Kavanagh's ‘how we vote now’

Abstract

We have performed a series of measurements on H2CO Ã 1A2 v4 = 1 single rotational levels using Transient Gain Spectroscopy (TGS), which was designed to provide detailed information on state-to-state population transfer and on the relaxation and transfer of rotational alignment. Measurements of the time dependence of the population of the directly populated JKa,Kc = 10,1 level, and of the population that is collisionally transferred to the neighboring 00,0, 20,2, and 30,3 rotational levels, are performed with both parallel and perpendicular relative PUMP/PROBE polarizations. This procedure allows the rotational-state-resolved populations to be analyzed with a microscopic M-resolved kinetic model at a level of detail unprecedented for a polyatomic molecule. Our analysis is able to distinguish direct, single-collision dealignment from sequential processes that result in dealignment. Nonlinear fitting of these data with a number of kinetic models indicates that there is no detectable contribution from single-collision direct-elastic events to the observed dealignment signals, and that dealignment may be accurately modeled by sequential processes following electric-dipole a-dipole selection rules. Furthermore, state-to-state inelastic rates are found to partition into MJ-resolved collisional transfer rates according to tensor opacity rank Λ = 1 (electric-dipole amplitudes), with no detectable contribution from Λ = 2 or Λ = 3. Tensor opacity rank Λ = 1 produces the greatest persistence of the MJ quantum number consistent with collisions in an isotropic environment, and this high level of MJ conservation is necessary to explain our data. An Energy-Corrected Sudden (ECS) scaling model, with collision duration τc = 7.0 psec, and basis rate coefficient k0←1 = 26.6(5) μsec−1 Torr−1 provides an excellent representation of the observed energy transfer, with no detectable contribution from higher order terms, or from terms deviating from ECS scaling.