Download or read book Molecular Beam Photodissociation Studies of Polyatomic Molecules and Radicals written by Eric J. Hintsa and published by . This book was released on 1989 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Proposed Molecular Beam Determination of Energy Partition in the Photodissociation of Polyatomic Molecules written by Richard N. Zare and published by . This book was released on 1964 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Energy Research Abstracts written by and published by . This book was released on 1995 with total page 782 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Molecular Beam Studies of Selected Radical Isomers and Photolytic Precursors written by Melita Luise Morton and published by . This book was released on 2002 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book PROPOSED MOLECULAR BEAM DETERMINATION OF ENERGY PARTITION IN THE PHOTODISSOCIATION OF POLYATOMIC MOLECULES written by and published by . This book was released on 1964 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Molecular Beam Studies of Reaction Dynamics written by and published by . This book was released on 1990 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: The major thrust of this research project is to elucidate detailed dynamics of simple reactions that are theoretically important and to unravel the mechanism of complex chemical reactions or photochemical processes that play important roles in many macroscopic processes. Molecular beams of reactants are used to study individual reactive encounters between molecules or to monitor photodissociation events in a collision-free environment. Most of the information is derived from measurement of the product fragment energy, angular, and state distributions. Recent activities are centered on the mechanisms of elementary chemical reactions involving oxygen atoms with unsaturated hydrocarbons, the dynamics of endothermic substitution reactions, the dependence of the chemical reactivity of electronically excited atoms on the alignment of excited orbitals, the primary photochemical processes of polyatomic molecules, intramolecular energy transfer of chemically activated and locally excited molecules, the energetics of free radicals that are important to combustion processes, the infrared-absorption spectra of carbonium ions and hydrated hydronium ions, and bond-selective photodissociation through electric excitation. 34 refs.

Download or read book Photodissociation Studies of Combustion Relevant Radical Molecules written by Mark Jeffrey Shapero and published by . This book was released on 2017 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt: The photodissociation of several combustion relevant radical molecules has been carried out. These species behave significantly different from closed shell species and the experiments presented here provide fundamental new insights into the chemical dynamics of free radicals. The experiments were carried out on a molecular beam photofragment translational spectroscopy instrument. Radicals were generated by flash pyrolysis of a suitable precursor and entrained in a pulsed molecular beam. The radicals were then photodissociated and the products were detected with a rotatable mass spectrometer based on electron impact ionization. The benzyl radical photodissociation and the cyclopentadienyl radical photodissociation were investigated at 248 nm. Two dissociation channels were observed for each radical. The benzyl radical dissociates into H + C7H6 and CH3 + C6H4 and the cyclopentadienyl radical dissociates to H + C5H4 and C3H3 + C2H2, where the C5H4 fragment was identified as ethynylallene by its ionization energy. The translational energy distribution determined for each channel suggests that every dissociation mechanism occurs via internal conversion to the ground state followed by intramolecular vibrational redistribution and dissociation. The branching ratio between the two competing channels for each radical was measured experimentally and compared to RRKM (Rice-Ramspberger-Kassel-Marcus) calculations. For both radicals, the dominant experimental channel was corroborated by RRKM calculations.

Download or read book Molecular Beam Studies of Photodissociation Reactions written by Douglas John Krajnovich and published by . This book was released on 1983 with total page 736 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book UV photodissociation Dynamics of Small Molecules and Free Radicals Studied by High n Rydberg H Atom Time of Flight Spectroscopy written by Gabriel Alejandro Amaral and published by . This book was released on 2001 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Photodissociation Studies of Polyatomic Free Radicals written by and published by . This book was released on 1993 with total page 147 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental program in gas phase polyatomic photochemistry and photophysics has been extablished in the Department of Chemistry at the University of Puerto Rico. Real time dynamics of sulfur monoxide photoelimination reactions have been studied by laser induced fluorescence spectroscopy of the nascent SO fragment on the B3 sigma ( - ) -X3 sigma ( - ) transition in the region of 237-295 nm. The group of molecules under investigation are Sulfur dioxide (SO2), dimethyl sulfoxide (CH3)2SO), and the thionyl halides (SOX2; where X = F, Cl or Br). In all of these experiments, the parent molecule is irradiated with an excimer laser (either 193 or 248 nm) and the energy disposal into the nascent SO photofragment is determined, and used as a mechanistic probe. The experiments indicate that the several of these parent molecules undergo three body dissociations. A second set of experiments measures kinetic decay constants of the C2H3O, both in the ground state and in the excited state. The temperature (295-374K) and pressure (2.5-100 torr) dependences for the rate constant of the C2H30 + N02 reaction have been measured by laser flash photolysis/laser induced fluorescence kinetic spectroscopy. The temperature dependent reaction for the decay of C2H3O in the presence of N02 is characterized over the measured region by the rate expression, k sub II = (1.48 +/-0.70)xlO(exp-11) exp(80.7 +/- 23.4K/T)cu cm/molecule/s. Fluorescence decay rates were determined in the presence to ten collision partners: He, Ar, N2, 02, CO, H2, HCl, C02, C2H4, and CH30CH = CH2. The measured electronic quenching cross-sections vary from 0.01 - 66.5 A2. A vibrational level dependence was found for the radiative lifetimes.

Download or read book Collision Dynamics of Methyl Radicals and Highly Vibrationally Excited Molecules Using Crossed Molecular Beams written by and published by . This book was released on 1991 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt: The vibrational to translational (V-->T) energy transfer in collisions between large highly vibrationally excited polyatomics and rare gases was investigated by time-of-flight techniques. Two different methods, UV excitation followed by intemal conversion and infrared multiphoton excitation (IRMPE), were used to form vibrationally excited molecular beams of hexafluorobenzene and sulfur hexafluoride, respectively. The product translational energy was found to be independent of the vibrational excitation. These results indicate that the probability distribution function for V-->T energy transfer is peaked at zero. The collisional relaxation of large polyatomic molecules with rare gases most likely occurs through a rotationally mediated process. Photodissociation of nitrobenzene in a molecular beam was studied at 266 nm. Two primary dissociation channels were identified including simple bond rupture to produce nitrogen dioxide and phenyl radical and isomerization to form nitric oxide and phenoxy radical. The time-of-flight spectra indicate that simple bond rupture and isomerization occurs via two different mechanisms. Secondary dissociation of the phenoxy radicals to carbon monoxide and cyclopentadienyl radicals was observed as well as secondary photodissociation of phenyl radical to give H atom and benzyne. A supersonic methyl radical beam source is developed. The beam source configuration and conditions were optimized for CH3 production from the thermal decomposition of azomethane. Elastic scattering of methyl radical and neon was used to differentiate between the methyl radicals and the residual azomethane in the molecular beam.

Download or read book ERDA Energy Research Abstracts written by and published by . This book was released on 1983 with total page 1028 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Crossed Molecular Beam Studies of the Reactions of Oxygen and Fluorine Atoms written by Y. T. Lee and published by . This book was released on 1985 with total page 83 pages. Available in PDF, EPUB and Kindle. Book excerpt: This annual report describes the primary photodissociation of acetylene (C2H2) and bromoiodomethane (CH2BrI) using a new molecular beam photofragmentation translational spectrometer. The new third generation molecular beam photofragmentation translational spectrometer constructed during the past year is described in detail. This apparatus incorporates many new ideas and allows us to study some of the primary dissociation processes of polyatomic molecules which were not possible in the past. The dissociation of Ch2BrI at 248 and 193 nm is extremely interesting. The competition between C-I and CC-Br bond rupture is the key question, but dissociations at 193 nm also produces IBr products. Secondary photodissociations of primary products were also found to be important. These two systems are carried out partly for the purpose of evaluating the performance of the new molecular beam photofragmentation apparatus. The results clearly show that the performance of the apparatus is as good as our original expectation and that it should be capable of handling molecules with very low vapor pressures; studies of these molecules, such as the nitroamines, are planned. Additional keywords: Unimolecular decay photochemistry; rocket fuels; energetic materials; polyatomic molecules; Naval Research. (Author).

Download or read book Vacuum Ultraviolet Photoionization and Photodissociation of Molecules and Clusters written by Cheuk-Yiu Ng and published by World Scientific. This book was released on 1991 with total page 590 pages. Available in PDF, EPUB and Kindle. Book excerpt: This monograph reviews the recent progress in vacuum ultraviolet (VUV) photoionization and photodissociation processes. Photoionization, photoelectron, and fluorescence spectroscopic techniques have played an important role in revealing the photoionization and photodissociation dynamics of molecules in the vacuum ultraviolet region and in providing accurate energetic and spectroscopic information of ions as well as neutral molecules. The book represents the first detailed review of major experimental developments in the studies of single vacuum ultraviolet photon ionization and dissociation processes of gaseous molecules and clusters.

Download or read book Fast Beam Studies of Free Radical Photodissociation written by Douglas Robert Cyr and published by . This book was released on 1993 with total page 446 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Multiple Photon Excitation and Dissociation of Polyatomic Molecules written by Cyrus D. Cantrell and published by Springer Science & Business Media. This book was released on 2013-03-08 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the early 1970s, researchers in Canada, the Soviet Union and the United States discovered that powerful infrared laser pulses are capable of dissociating mole cules such as SiF4 and SF6' This result, which was so unexpected that for some time the phenomenon of multiple-photon dissociation was not recognized in many cir cumstances in which we now know that it occurs, was first publicized at a time when the possibility of using lasers for the separation of isotopes had attracted much attention in the scientific community. From the mid-1970s to the early 1980s, hun dreds of experimental papers were published describing the multiple-photon absorp tion of C02 laser pulses in nearly every simple molecule with an absorption band in the 9 - 11 jJm region. Despite this impressive volume of experimental results, and despite the efforts of numerous theorists, there is no agreement among re searchers in the field on many fundamental aspects of the absorption of infrared laser light by polyatomic molecules. This book is devoted to reviells of the experimental and theoretical research that provides the foundations for our current understanding of molecular multiple photon exc itat i on, and to rev i ews of research that is pert i nent to the 1 aser sep aration of isotopes.

Download or read book The Chemical Dynamics and Kinetics of Small Radicals written by Ketian Liu and published by World Scientific. This book was released on 1996-01-19 with total page 616 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book highlights recent progress in the chemistry of radicals. Developments include the growing use of lasers to generate radicals, the application of lasers to provide state, angular, polarization, energy and real-time resolution in kinetics and dynamics experiments, the development of theories for handling the reactions of radicals, and the simulation of the reaction dynamics of increasingly larger systems for direct comparison to experimental results. The book emphasizes the increasing interaction between experimental dynamics, kinetics and theory. It is appropriate for chemistry graduate students and researchers about to enter the field. However, the discussions of some topics progress to a more advanced level so that even an expert will find the book useful.