Read Books Online and Download eBooks, EPub, PDF, Mobi, Kindle, Text Full Free.
Photofragment Translational Spectroscopy Of Three Body Dissociations And Free Radicals
Download Photofragment Translational Spectroscopy Of Three Body Dissociations And Free Radicals full books in PDF, epub, and Kindle. Read online Photofragment Translational Spectroscopy Of Three Body Dissociations And Free Radicals ebook anywhere anytime directly on your device. Fast Download speed and no annoying ads. We cannot guarantee that every ebooks is available!
Book Synopsis Photofragment Translational Spectroscopy of Three Body Dissociations and Free Radicals by :
Download or read book Photofragment Translational Spectroscopy of Three Body Dissociations and Free Radicals written by and published by . This book was released on 1995 with total page 235 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation describes several three-body dissociations and the photodissociation of methyl radicals studied using photofragment translational spectroscopy. The first chapter provides an introduction to three body dissociation, examines current experimental methodology, and includes a discussion on the treatment of photofragment translational spectroscopy data arising from three-body fragmentation. The ultraviolet photodissociation of azomethane into two methyl radicals and nitrogen is discussed in chapter 2. Chapter 3 describes the photodissociation of acetone at 248 nm and 193 nm. At 248 nm the translational energy release from the initial C-C bond cleavage matches the exit barrier height and a comparison with results at 266 nm suggests that E{sub T} is invariant to the available energy. A fraction of the nascent CH3CO radicals spontaneously dissociate following rotational averaging. The E{sub T} for the second C-C bond cleavage also matches the exit barrier height. At 193 nm the experimental data can be successfully fit assuming that the dynamics are analogous to those at 248 nm. A simplified model of energy partitioning which adequately describes the experimental results is discussed. Experiments on acetyl halides provide additional evidence to support the proposed acetone dissociation mechanism. A value of 17.0"1.0 kcal/mole for the barrier height, CH3CO decomposition has been determined. The photodissociation of methyl radical at 193 nm and 212.8 nm is discussed in the chapter 5. The formation of CH2 (1A{sub l}) and H (2S) was the only single photon dissociation pathway observed at both wavelengths.
Book Synopsis Photofragment Translational Spectroscopy of Three Body Dissociations and Free Radicals by : Simon William North
Download or read book Photofragment Translational Spectroscopy of Three Body Dissociations and Free Radicals written by Simon William North and published by . This book was released on 1995 with total page 510 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Photodissociation Spectroscopy and Dynamics of Free Radicals, Clusters, and Ions by : Hyeon Choi
Download or read book Photodissociation Spectroscopy and Dynamics of Free Radicals, Clusters, and Ions written by Hyeon Choi and published by . This book was released on 1999 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Dissertation Abstracts International by :
Download or read book Dissertation Abstracts International written by and published by . This book was released on 2004 with total page 882 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Studies of Photofragment Translational Spectroscopy by : Scott Johnathan Goncher
Download or read book Studies of Photofragment Translational Spectroscopy written by Scott Johnathan Goncher and published by . This book was released on 2008 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Photoisomerization and Photodissociation Dynamics of Reactive Free Radicals by :
Download or read book Photoisomerization and Photodissociation Dynamics of Reactive Free Radicals written by and published by . This book was released on 2000 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt: The photofragmentation pathways of chemically reactive free radicals have been examined using the technique of fast beam photofragment translational spectroscopy. Measurements of the photodissociation cross-sections, product branching ratios, product state energy distributions, and angular distributions provide insight into the excited state potential energy surfaces and nonadiabatic processes involved in the dissociation mechanisms. Photodissociation spectroscopy and dynamics of the predissociative {tilde A}2A1 and {tilde B}2A2 states of CH3S have been investigated. At all photon energies, CH3 + S(3P{sub j}), was the main reaction channel. The translational energy distributions reveal resolved structure corresponding to vibrational excitation of the CH3 umbrella mode and the S(3P{sub j}) fine-structure distribution from which the nature of the coupled repulsive surfaces is inferred. Dissociation rates are deduced from the photofragment angular distributions, which depend intimately on the degree of vibrational excitation in the C-S stretch. Nitrogen combustion radicals, NCN, CNN and HNCN have also been studied. For all three radicals, the elimination of molecular nitrogen is the primary reaction channel. Excitation to linear excited triplet and singlet electronic states of the NCN radical generates resolved vibrational structure of the N2 photofragment. The relatively low fragment rotational excitation suggests dissociation via a symmetric C{sub 2V} transition state. Resolved vibrational structure of the N2 photofragment is also observed in the photodissociation of the HNCN radical. The fragment vibrational and rotational distributions broaden with increased excitation energy. Simple dissociation models suggest that the HNCN radical isomerizes to a cyclic intermediate (c-HCNN) which then dissociates via a tight cyclic transition state. In contrast to the radicals mentioned above, resolved vibrational structure was not observed for the ICNN radical due to extensive fragment rotational excitation, suggesting that intermediate bent states are strongly coupled along the dissociation pathway. The measurements performed in this Thesis have additionally refined the heats of formation and bond dissociation energies of these radicals and have unambiguously confirmed and added to the known electronic spectroscopy.
Book Synopsis Production and Photodissociation of Neutral Free Radicals by : Neil Charles Cole-Filipiak
Download or read book Production and Photodissociation of Neutral Free Radicals written by Neil Charles Cole-Filipiak and published by . This book was released on 2015 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt: The primary photochemistry of several combustion-relevant free radicals have been in- vestigated via photofragment translational spectroscopy. The relevance of radical photo- chemistry will be discussed, along with methodologies and details of each experiment. The experimental apparatus will also be described, especially with regard to the recent installa- tion of a tunable energy electron ionizer. The upgraded ionizer has been a significant advance, allowing for more detailed characterization of the radical source employed in this thesis. The photochemistry of the phenyl radical (c-C6H5), a combustion intermediate and pre- cursor to polycyclic aromatic hydrocarbons, was investigated at 248 and 193 nm. At 248 nm, an H-atom loss pathway was found, while at 193 nm both H-atom loss and C2H2 loss pathways were observed. For both wavelengths, P(ET) distributions suggested internal con- version to the ground electronic state followed by energy randomization and dissociation. The branching ratio between the two 193 nm dissociation pathways was found to be 0.2 ± 0.1 in favor of H-atom loss, in good agreement with statistical Rice-Rampsperger-Kassel-Marcus (RRKM) theory. An initial investigation of the methyl perthiyl radical (CH3SS) at 248 nm suggested the surprising results of both CH3 + SS and CH2S + SH dissociation channels with no evidence for S-atom loss. In both cases, the translational energy distributions were inconsistent with the expected energetics. Upon reinvestigation, the assumption of radical production--and there- fore radical photodissociation--was shown to be incorrect. The new results demonstrated S-loss and CH3 loss pathways, with the former appearing to involve a repulsive electronic excited state.
Book Synopsis Fast Beam Studies of Free Radical Photodissociation by :
Download or read book Fast Beam Studies of Free Radical Photodissociation written by and published by . This book was released on 1993 with total page 459 pages. Available in PDF, EPUB and Kindle. Book excerpt: The photodissociation of free radicals is studied in order to characterize the spectroscopy and dissociation dynamics of the dissociative electronic states in these species. To accomplish this, a novel method of radical production, based on the photodetachment of the corresponding negative ion, has been combined with a highly complementary form of photofragment translational spectroscopy. The optical spectroscopy of transitions to dissociative states is determined by monitoring the total photofragment yield as a function of dissociation photon energy. Branching ratios to various product channels, internal energy distributions of the fragments, bond dissociation energies, and the translational energy-dependent photofragment recoil angular distributions are then determined at selected excitation energies. A detailed picture of the dissociation dynamics can then be formulated, allowing insight concerning the interactions of potential energy surfaces involved in the dissociation. After an introduction to the concepts and techniques mentioned above, the experimental apparatus used in these experiments is described in detail. The basis and methods used in the treatment of data, especially in the dissociation dynamics experiments, are then put forward.
Book Synopsis Fast Beam Investigations of Two- and Three-Body Photodissociation by Time- and Position-Coincidence Imaging by : Paul Crider
Download or read book Fast Beam Investigations of Two- and Three-Body Photodissociation by Time- and Position-Coincidence Imaging written by Paul Crider and published by . This book was released on 2010 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fast beam photofragment translational spectroscopy has been used to elucidate the photodissociation dynamics of small radicals and closed-shell anions. Imaging of photofragments in time- and position-coincidence allows the determination of mass distributions, translational energy distributions [P(ET) distributions], and in the case of three-body fragmentation channels, ternary Dalitz plots depicting the momentum disposal among the fragments. These data yield information about the potential energy surfaces responsible for dissociation as well dynamic and kinematic information about the decay mechanism itself. Chapter 1 presents a brief overview of photodissociation dynamics and photofragment translational spectroscopy and some recurring themes of the research presented in this Thesis are explored. The use of Dalitz plots in kinematic analysis of three-body dissociation is discussed in detail. Chapters 2 and 3 present, respectively, experimental and theoretical findings on the photodissociation of perdeuterated C3D3 isotopologs, propargyl (D2CCCD) and propynyl (CCCD3) at 248 and 193 nm. Mass distributions reveal D2 loss and three heavy mass channels: CD + C2D2, CD2 + C2D, and CD3 + C2. The D loss channel is present, but incompatible with our detection scheme and thus was not observed. P(ET) distributions indicate each dissociation proceeds by internal conversion followed by statistical dissociation on the ground state surface. In Chapter 3, results of high level ab initio calculations are presented and RRKM rate constants are determined. Chapter 4 presents results on two- and three-body photodissociation dynamics of I2Br & hibar; from 300 to 270 nm. Two- and three-body dissociation is observed throughout this wavelength range. Four distinct two-body channels are observed: Br- + I2, I- + IBr, Br + I2-, and I + IBr-. Dalitz plots indicate three-body dissociation occurs primarily by a concerted decay mechanism. A sequential dissociation mechanism, where Br- + I2(B) is followed by electronic predissociation of the metastable I2(B) fragment into ground state I atoms is reported. Chapter 5 presents preliminary results of two- and three-body photodissociation of ozone at 193 and 157 nm. Ozone is prepared by photodetachment of ozonide at 386 nm (about 1.1 eV above the detachment energy). Greater than expected kinetic energy release is observed for both wavelengths in the P(ET) distributions. The additional energy is attributed to two sources: extra energy available by photodetaching far above the electron affinity of ozone, and extra internal energy in the ozonide precursor. Three-body dissociation occurs at 193 nm as a 3.6% channel and at 157 nm as a 19.2% channel. Three-body dissociation proceeds at both wavelengths by a synchronous, concerted decay mechanism.
Book Synopsis Scientific and Technical Aerospace Reports by :
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 818 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Investigations of Two- and Three-Body Molecular Photodissociation Dynamics by Fast Beam Photofragment Translational Spectroscopy by : Aaron Woods Harrison
Download or read book Investigations of Two- and Three-Body Molecular Photodissociation Dynamics by Fast Beam Photofragment Translational Spectroscopy written by Aaron Woods Harrison and published by . This book was released on 2014 with total page 95 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 1995-12 with total page 896 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Photodissociaion Dynamics of Neutral Free Radicals by : Bogdan Negru
Download or read book Photodissociaion Dynamics of Neutral Free Radicals written by Bogdan Negru and published by . This book was released on 2012 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: Photofragment translational spectroscopy was used to study the photodissociation dynamics of the phenyl and tert-butyl radicals. These radicals were produced in a collisionless environment from the flash pyrolysis of the appropriate precursor, nitrosobenzene for phenyl and azo-tert-butane for the tert-butyl radical. The photodissociation dynamics of the phenyl radical (C6H5) were investigated at 248 and 193 nm. At 248 nm, the only dissociation products observed were from hydrogen atom loss, attributed primarily to H + o-C6H4 (ortho-benzyne). The observed translational energy distribution was consistent with statistical decay on the ground state surface. At 193 nm, dissociation to H + C6H4 and C4H3 + C2H2 was observed. The C6H4 fragment can be either o-C6H4 or l-C6H4 resulting from opening of the phenyl ring. The C4H3 + C2H2 products dominate over the two H loss channels. Attempts to reproduce the observed branching ratio by assuming ground state dynamics were unsuccessful. This discord, between the experimentally observed branching ratio and the theoretically predicted branching ratio led us to reinvestigate the dissociation dynamics of the phenyl radical at 193 nm, while producing the radical under different source conditions. The photodissociation dynamics of the tert-butyl radical (t-C4H9) were investigated at 248 nm. Two distinct channels of approximately equal importance were identified: dissociation to H + 2-methylpropene (C4H8), and CH3 + dimethylcarbene (C3H6). Neither the translational energy distributions that describe these two channels nor the product branching ratio are consistent with statistical dissociation on the ground state, and instead favor a mechanism taking place on excited state surfaces. The studies presented in this dissertation show that although hydrogen atom loss is sometimes expected to be the only major dissociation pathway in the photodissociation of hydrocarbon radicals this is not always a justified assumption.
Book Synopsis Photoionization and Photodetachment by : Cheuk-Yiu Ng
Download or read book Photoionization and Photodetachment written by Cheuk-Yiu Ng and published by World Scientific. This book was released on 2000 with total page 1415 pages. Available in PDF, EPUB and Kindle. Book excerpt: Owing to the advances of vacuum ultraviolet and ultrafast lasers and third generation synchrotron sources, the research on photoionization, photoelectrons, and photodetachment has gained much vitality in recent years. These new light sources, together with ingenious experimental techniques, such as the coincidence imaging, molecular beam, pulsed field ionization photoelectron, mass-analyzed threshold ion, and pulsed field ion pair schemes, have allowed spectroscopic, dynamic, and energetic studies of gaseous species to a new level of detail and accuracy. Profitable applications of these methods to liquids are emerging.This invaluable two-volume review consists of twenty-two chapters, focusing on recent developments in photoionization and photodetachment studies of atoms; molecules, transient species, clusters, and liquids.
Book Synopsis Government Reports Announcements & Index by :
Download or read book Government Reports Announcements & Index written by and published by . This book was released on 1996 with total page 776 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Photoionization And Photodetachment (In 2 Parts) by : Cheuk-yiu Ng
Download or read book Photoionization And Photodetachment (In 2 Parts) written by Cheuk-yiu Ng and published by World Scientific. This book was released on 2000-06-30 with total page 684 pages. Available in PDF, EPUB and Kindle. Book excerpt: Owing to the advances of vacuum ultraviolet and ultrafast lasers and third generation synchrotron sources, the research on photoionization, photoelectrons, and photodetachment has gained much vitality in recent years. These new light sources, together with ingenious experimental techniques, such as the coincidence imaging, molecular beam, pulsed field ionization photoelectron, mass-analyzed threshold ion, and pulsed field ion pair schemes, have allowed spectroscopic, dynamic, and energetic studies of gaseous species to a new level of detail and accuracy. Profitable applications of these methods to liquids are emerging.This invaluable two-volume review consists of twenty-two chapters, focusing on recent developments in photoionization and photodetachment studies of atoms; molecules, transient species, clusters, and liquids.
Book Synopsis Fast Beam Studies of Free Radical Photodissociation by : Douglas Robert Cyr
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 526 pages. Available in PDF, EPUB and Kindle. Book excerpt:
