| Zero Electron Kinetic Energy/Velocity Map Imaging (ZEKE/VMI) spectroscopy of Negative Ions |
22 SEP 2004 |
3 pages |
| Authors:
Daniel M. Neumark; CALIFORNIA UNIV BERKELEY SPONSORED PROJECTS OFFICE
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 | Construction of the slow photoelectron, velocity-map imaging (SEVI) instrument was completed and the first results were obtained, demonstrating the power of the technique in measuring high-resolution (approx. 0.5 meV) photodetachment spectra of negative ions. Work is continuing on improving the performance of this instrument, with particular focus on reducing stray magnetic fields in the detection region and modifying the ion source and mass spectrometer to achieve higher ion signal and ... |
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| Studies of Transition States and Cluster-Induced Reactivity Via Negative Ion Photoelectron Spectroscopy |
JAN 2003 |
9 pages |
| Authors:
Daniel M. Neumark; CALIFORNIA UNIV BERKELEY SPONSORED PROJECTS OFFICE
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| Research during the last three years has focused on using negative ion photoelectron (PE) spectroscopy and zero electron kinetic energy (ZEKE) spectroscopy to probe the effects of clustering on the energetics, spectroscopy, and dynamics of ions and transition states, and to investigate the ground and excited electronic states of reactive free radicals. We have also developed a new spectroscopic method in which stimulated Raman pumping combined with PE spectroscopy is ... |
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| Spectroscopy of Anion and Transition States Using Stimulated Raman Pumping |
14 JAN 2000 |
10 pages |
| Authors:
Daniel M. Neumark; CALIFORNIA UNIV BERKELEY SPONSORED PROJECTS OFFICE
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| During the last grant period, we have used negative ion photoelectron spectroscopy (PES) and ZEKE spectroscopy to probe the spectroscopy and dynamics of negatively-charged and neutral species. Specific areas include (a) ZEKE spectroscopy of diatomic rare gas halides RgX(-)and clusters of the form Rg(n) X(-), (b) PES of I2(-)Ar(n) and I2(-) (CO2)n, in which the effects of solvation on a molecular (as opposed to atomic) ion ... |
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| Transition State Spectroscopy by Photodetachment of Vibrationally Excited Atoms |
13 MAR 97 |
8 pages |
| Authors:
Daniel M. Neumark; CALIFORNIA UNIV BERKELEY
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| The research supported by this grant centers on the spectroscopy and dynamics of a variety of transient species including transition states, clusters, and free radicals. These species lie at the heart of many chemical processes, and our experiments have provided unprecedented insight into their nature. The novel feature of this program is that negative ion spectroscopy is used as the basic experimental tool in all of these experiments, because in ... |
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| Photo-Initiated Ion-Molecular Reactions in Size-Selected Clusters |
30 NOV 96 |
3 pages |
| Authors:
Daniel M. Neumark; CALIFORNIA UNIV BERKELEY DEPT OF CHEMISTRY
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| During the grant period, this work has focused on two research areas: zero electron kinetic energy (ZEKE) spectroscopy experiments on mass-selected cluster anions in which a halide ion (C1 or I) is solvated with a known number of rare gas atoms, and stimulated Raman pumping of negative ions. Negative ion ZEKE spectroscopy is a high resolution laser photodetachment experiment which yields information on the vibrational and electronic spectroscopy of both ... |
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| Study of Anion-Molecule Reaction Dynamics with Time-Dependent Photoelectron Spectroscopy |
21 FEB 96 |
3 pages |
| Authors:
Daniel M. Neumark; CALIFORNIA UNIV BERKELEY SPONSORED PROJECTS OFFICE
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| A novel femtosecond time-resolved experiment has been set up to probe the photodissociation dynamics of negative ions and negative ion clusters. First results for the photodissociation of I2 have been obtained recently. jg p1 |
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| Spectroscopy of the Transition State Region in Hydrogen Transfer Reactions |
09 AUG 94 |
6 pages |
| Authors:
Daniel M. Neumark; CALIFORNIA UNIV BERKELEY SPONSORED PROJECTS OFFICE
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| The research supported by this grant is centered on probing the spectroscopy and dynamics of a variety of transient species using two anion photodetachment techniques: photoelectron spectroscopy and zero electron kinetic energy spectroscopy. Most of the research effort was devoted to the transition state spectroscopy of reactions involving H atom abstraction by fluorine atoms. We have also measured electron affinities of several radicals, and have characterized several of the excited ... |
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| Threshold Photodetachment Spectroscopy |
03 SEP 92 |
5 pages |
| Authors:
Daniel M. Neumark; CALIFORNIA UNIV BERKELEY DEPT OF CHEMISTRY
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| The goal of this project is to learn about the electronic and vibrational spectroscopy of size-selected clusters. This is done using high resolution negative ion photodetachment techniques developed in our laboratory during the last four years. In our experiments, a beam of cluster anions (typically Cn- or Sin-) is generated using a laser vaporization source, mass- selected, and photodetached with a fixed frequency or tunable laser. In the fixed-frequency experiments, ... |
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| Negative Ion Photodetachment as a Probe of the Transition State Region: The I + HI Reaction |
30 APR 91 |
42 pages |
| Authors:
Daniel M. Neumark; CALIFORNIA UNIV BERKELEY DEPT OF CHEMISTRY
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| The study of the transition state of bimolecular reactions using negative ion photodetachment is described. The I + HI reaction is used as an example of this method. The photoelectron spectrum of IHI(-) shows resolved vibrational features assigned to a progression in the antisymmetric stretch mode of the neutral IHI complex. Threshold photodetachment studies of this system at higher resolution show additional structure that arises from two sources: (1) resonances ... |
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| Spectroscopy of the Transition State Region in Chemical Reactions |
31 OCT 90 |
7 pages |
| Authors:
Daniel M. Neumark; CALIFORNIA UNIV BERKELEY SPONSORED PROJECTS OFFICE
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| During the three years of this grant, a negative ion time-of-flight photoelectron spectrometer was constructed and used in a series of novel experiments designed to probe the transition state region in chemical reactions. In addition, conventional photoelectron spectra of several anions with high electron binding energies were obtained. Cold negative ions are produced in an ion source based on a pulsed free jet expansion. The ions are mass selected using ... |
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| Transition State Spectroscopy of Hydrogen Transfer Reactions |
29 NOV 89 |
18 pages |
| Authors:
Daniel M. Neumark; CALIFORNIA UNIV BERKELEY DEPT OF CHEMISTRY
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| The transition state region for several chemical reactions of the type A + HB yields HA + B has been investigated via photodetachment of the stable negative ion AHB-. The photoelectron spectra of BrHBr- and BrHI- show resolved vibrational structure attributable to the transition state region of the Br + HBr and Br + Hi reactions, respectively. The photoelctron spectra of IDI- and the cluster ion IDI-(N2O) are compared; these ... |
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| Methylene Singlet-Triplet Energy Splitting by Molecular Beam Photodissociation of Ketene |
19 OCT 1981 |
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| Authors:
Carl C. Hayden; Daniel M. Neumark; Kosuke Shobatake; Randal K. Sparks; Yuan T. Lee; CALIFORNIA UNIV BERKELEY DEPT OF CHEMISTRY
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 | The singlet-triplet splitting in methylene has been determined from the measurements of fragment velocities from ketene photodissociation at 351 and 308 nm in a molecular beam. The splitting is found to be 8.5 + or - 0.8 kcal/ mole. This agrees with many experimental results, but not with the value of 19.5 kcal/mole derived from recent photodetachment experiments on CH2-. (Author) |
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Reports by Author
