Pulsed‐Laser Production and Detection of Spin‐Polarized Hydrogen Atoms

Abstract

Spin-polarized hydrogen (SPH) atoms have traditionally been produced and detected using complex experimental methods with poor time resolution. Recently, SPH has been produced by pulsed-laser photodissociation of HCl using circularly polarized light. In combination with the proposed detection of SPH via polarized fluorescence, this approach should allow the production and spatially resolved detection of SPH with a higher sensitivity than that currently available, and with a time resolution in the nanosecond regime. This represents an improvement of several orders of magnitude over the existing methods.

Measurement of Br photofragment orientation and alignment from HBr photodissociation: Production of highly spin-polarized hydrogen atoms

“…The degree of this polarization may be confirmed both directly 35 and theoretically, 36 and the polarization may increase at different photodissociation wavelengths. ͑8͒ and ͑21͒, and the measured values of a 0 (1) (Ќ) and a 0 (2) (Ќ), the nascent electron polarization for the H atoms ͑parallel to the photodissociation propagation direction͒ from the photodissociation of HBr is determined to be 86Ϯ27% ͑2͒.…”

Polarized electron-beam acceleration driven by vortex laser pulses

“…As stated above, preparation a pre-polarized electron target is crucial to our scheme. Known from previous literatures, the photodissociation of hydrogen halides with circularly polarized UV light yields highly spinpolarized hydrogen and halogen atoms [26,27], at gas densities of at least 10 19 cm −3 [28]. The polarization can approach 100% for specific photodissociation wavelengths (for HCl this is near 213 nm), and if the molecular bonds are aligned prior to photodissociation [25]; otherwise, if the bonds are isotropic, the polarization is reduced to 40%.…”

Spin-polarized hydrogen Rydberg time-of-flight: Experimental measurement of the velocity-dependent H atom spin-polarization

“…An alternative approach has been used by Rakitzis et al 13,14 in which they measured the full angular momentum polarization of the halogen coproduct in dissociation of hydrogen chloride and hydrogen bromide, and used this to infer the H atom spin polarization. Rakitzis and co-workers 15 also reported one case in which they used detection of polarized Lyman-α fluorescence to measure the H atom electron spin polarization directly. This approach could not resolve the underlying velocity dependence, however, but was shown to give results consistent with the inferences based on the halogen atom polarization.…”