Pump-Probe spectroscopy with a femtosecond monochromatic VUV light source
POSTER
Abstract
A table-top pump-probe set-up combining our Vacuum Ultra-Violet (VUV) monochrometor and cold target recoil-ion momentum spectroscopy (COLTRIMS) apparatus has been developed. High flux VUV photons are generated from a semi-infinite gas cell via high order harmonic generation. A dispersion-compensated grating pair is used to select a single harmonic with pulse duration below a 100 femtosecond. The VUV photon energy is tunable from 10 to 20 eV with a bandwidth of less than 200 meV. Such a VUV source can strongly interact with valence electrons of most molecules, thus trigger chemical reactions with well-defined time-energy information. A following synchronous infrared pulse is applied to probe or control the process. The reaction products are momentum-imaged in coincidence by the COLTRIMS system, thus enabling channel-resolved measurements. A few proof-of-principal experiments on the simplest molecular system, D$_{\mathrm{2}}$, are demonstrated.
*Supported by Chem. Sci. DOE DE-FG02-86ER1349, the National Science Foundation under CHE-0822646 and the U.S. Army Research Office under grant number W911NF-07-1-0475