Measurement of the Raman polarizability anisotropy for thev= 1 pure rotational Raman transition inH₂by rotational Raman spectroscopy

First accurate experimental study of Mu reactivity from a state-selected reactant in the gas phase: the Mu + H2{1} reaction rate at 300 K

“…The incident pump light is Raman scattered by H 2 molecules, exciting them through a virtual electronic state that then emits 683 nm Stokes light, populating the v = 1 level of H 2 , both transitions separately satisfying the normal parity selection rules in the process. The (v, J) selection rules for Raman scattering between ro-vibrational states of a diatomic like H 2 are Δv = ±1 and ΔJ = 0, ±2 [38,[47][48][49][50][51][52]54]. These are the same for SRP, proceeding through a virtual electronic state, as indicated in figure 1.…”

“…Lacking a dipole moment, direct laser-excitation of vibrational states is not possible in H 2 , necessitating our use of SRP [33]. This technique has a long history in pumping rovibrational excited states in hydrogen, and has been utilized extensively in studies of vibrational relaxation in H 2 [42][43][44][45][46][47][48][49][50][51] and in reaction dynamics studies with molecular beams [35,37,38,[52][53][54]. In the present work, 532 nm light, generated by an injection-seeded Nd:YAG laser (Continuum PowerLight 9025) with a FWHM linewidth of 0.003 cm −1 , FWHM pulse duration of ∼8 ns, pulse energy up to ∼550 mJ and repetition rate of 25 Hz, was used as a pump (see figure 1).…”