Paul Crider | University of California, Berkeley (original) (raw)
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Università degli Studi di Firenze (University of Florence)
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Papers by Paul Crider
The Journal of chemical physics, 2011
The photodissociation of gas-phase I 2 Br − was investigated using fast beam photofragment transl... more The photodissociation of gas-phase I 2 Br − was investigated using fast beam photofragment translational spectroscopy. Anions were photodissociated from 300 to 270 nm (4.13-4.59 eV) and the recoiling photofragments were detected in coincidence by a time-and position-sensitive detector. Both two-and three-body channels were observed throughout the energy range probed. Analysis of the two-body dissociation showed evidence for four distinct channels: Br − + I 2 , I − + IBr, Br + I − 2 , and I + IBr − . In three-body dissociation, Br( 2 P 3/2 ) + I( 2 P 3/2 ) + I − and Br − + I( 2 P 3/2 ) + I( 2 P 3/2 ) were produced primarily from a concerted decay mechanism. A sequential decay mechanism was also observed and attributed to Br − ( 1 S) + I 2 (B 3 + 0u ) followed by predissociation of I 2 (B).
The Journal of …, 2007
Van der Waals clusters serve as prototypical systems for studying processes of energy transfer. T... more Van der Waals clusters serve as prototypical systems for studying processes of energy transfer. The I 2 ·Ar system has attracted particular interest due to the wide array of decay processes occurring in competition with one another. Here, we present systematic dissociative photodetachment (DPD) studies of the I 2and I 2 -‚Ar anions in the region 4.24-4.78 eV. The resulting neutral fragments are detected by time-and positionsensitive (TPS) coincident imaging. Photofragment mass distributions and translational energy distributions from the DPD of I 2are presented and facilitate understanding of the I 2 ‚Ar system. For the I 2 ‚Ar complex, channels resulting from two-body dissociation leading to I 2 + Ar photoproducts are observed at all photon energies employed. We also report the first direct observation of the previously inferred three-body dissociation channel leading to I + I + Ar photoproducts. The relative intensities of each decay channel are investigated in relation to the electronic state being accessed. Translational energy distributions of the I 2 ‚Ar complex lend further insight into the decay mechanism for each channel.
The Journal of chemical …, 2009
The photodissociation of perdeuterated propargyl ͑D 2 CCCD͒ and propynyl ͑D 3 CCC͒ radicals was i... more The photodissociation of perdeuterated propargyl ͑D 2 CCCD͒ and propynyl ͑D 3 CCC͒ radicals was investigated using fast beam photofragment translational spectroscopy. Radicals were produced from their respective anions by photodetachment at 540 and 450 nm ͑below and above the electron affinity of propynyl͒. The radicals were then photodissociated at 248 or 193 nm. The recoiling photofragments were detected in coincidence with a time-and position-sensitive detector. Three channels were observed: D 2 loss, CD+ C 2 D 2 , and CD 3 +C 2 . Observation of the D loss channel was incompatible with this experiment and was not attempted. Our translational energy distributions for D 2 loss peaked at nonzero translational energy, consistent with ground state dissociation over small ͑Ͻ1 eV͒ exit barriers with respect to separated products. Translational energy distributions for the two heavy channels peaked near zero kinetic energy, indicating dissociation on the ground state in the absence of exit barriers.
The Journal of chemical physics, 2011
The photodissociation of gas-phase I 2 Br − was investigated using fast beam photofragment transl... more The photodissociation of gas-phase I 2 Br − was investigated using fast beam photofragment translational spectroscopy. Anions were photodissociated from 300 to 270 nm (4.13-4.59 eV) and the recoiling photofragments were detected in coincidence by a time-and position-sensitive detector. Both two-and three-body channels were observed throughout the energy range probed. Analysis of the two-body dissociation showed evidence for four distinct channels: Br − + I 2 , I − + IBr, Br + I − 2 , and I + IBr − . In three-body dissociation, Br( 2 P 3/2 ) + I( 2 P 3/2 ) + I − and Br − + I( 2 P 3/2 ) + I( 2 P 3/2 ) were produced primarily from a concerted decay mechanism. A sequential decay mechanism was also observed and attributed to Br − ( 1 S) + I 2 (B 3 + 0u ) followed by predissociation of I 2 (B).
The Journal of …, 2007
Van der Waals clusters serve as prototypical systems for studying processes of energy transfer. T... more Van der Waals clusters serve as prototypical systems for studying processes of energy transfer. The I 2 ·Ar system has attracted particular interest due to the wide array of decay processes occurring in competition with one another. Here, we present systematic dissociative photodetachment (DPD) studies of the I 2and I 2 -‚Ar anions in the region 4.24-4.78 eV. The resulting neutral fragments are detected by time-and positionsensitive (TPS) coincident imaging. Photofragment mass distributions and translational energy distributions from the DPD of I 2are presented and facilitate understanding of the I 2 ‚Ar system. For the I 2 ‚Ar complex, channels resulting from two-body dissociation leading to I 2 + Ar photoproducts are observed at all photon energies employed. We also report the first direct observation of the previously inferred three-body dissociation channel leading to I + I + Ar photoproducts. The relative intensities of each decay channel are investigated in relation to the electronic state being accessed. Translational energy distributions of the I 2 ‚Ar complex lend further insight into the decay mechanism for each channel.
The Journal of chemical …, 2009
The photodissociation of perdeuterated propargyl ͑D 2 CCCD͒ and propynyl ͑D 3 CCC͒ radicals was i... more The photodissociation of perdeuterated propargyl ͑D 2 CCCD͒ and propynyl ͑D 3 CCC͒ radicals was investigated using fast beam photofragment translational spectroscopy. Radicals were produced from their respective anions by photodetachment at 540 and 450 nm ͑below and above the electron affinity of propynyl͒. The radicals were then photodissociated at 248 or 193 nm. The recoiling photofragments were detected in coincidence with a time-and position-sensitive detector. Three channels were observed: D 2 loss, CD+ C 2 D 2 , and CD 3 +C 2 . Observation of the D loss channel was incompatible with this experiment and was not attempted. Our translational energy distributions for D 2 loss peaked at nonzero translational energy, consistent with ground state dissociation over small ͑Ͻ1 eV͒ exit barriers with respect to separated products. Translational energy distributions for the two heavy channels peaked near zero kinetic energy, indicating dissociation on the ground state in the absence of exit barriers.