title: Enhanced sensitivity in H photofragment detection by two-color reduced-Doppler ion imaging.
abstract: Two-color reduced-Doppler (TCRD) and one-color velocity map imaging (VMI) were used for probing H atom photofragments resulting from the ~243.1 nm photodissociation of pyrrole. The velocity components of the H photofragments were probed by employing two counterpropagating beams at close and fixed wavelengths of 243.15 and 243.12 nm in TCRD and a single beam at ~243.1 nm, scanned across the Doppler profile in VMI. The TCRD imaging enabled probing of the entire velocity distribution in a single pulse, resulting in enhanced ionization efficiency, as well as improved sensitivity and signal-to-noise ratio. These advantages were utilized for studying the pyrrole photodissociation at ~243.1 and 225 nm, where the latter wavelength provided only a slight increase in the H yield over the self-signal from the probe beams. The TCRD imaging enabled obtaining high quality H(+) images, even for the low H photofragment yields formed in the 225 nm photolysis process, and allowed determining the velocity distributions and anisotropy parameters and getting insight into pyrrole photodissociation.
authors: Department of Physics, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel.
authors: Michael
authors: M
authors: Epshtein
authors: Alexander
authors: A
authors: Portnov
authors: Rotem
authors: R
authors: Kupfer
authors: Salman
authors: S
authors: Rosenwaks
authors: Ilana
authors: I
authors: Bar