Download or read book On the Collision Mechanism of Bimolecular Reactions The stripping mechanism of the reactions Ar H2 D2 right arrow ArH H ArD D at energies 20 eV written by A. Henglein and published by . This book was released on 1968 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book On the Collision Mechanism of Bimolecular Reactions Part II The Stripping Mechanism of the Reactions Ar H2 D2 to ArH H ArD D at Energies 20 EV written by K. Lacmann and published by . This book was released on 1968 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: The bands of ArH(+) and ArD(+) ions have been observed in the velocity spectra of the ions resulting from the interaction (chemical reaction and scattering) of Ar(+) ions with H2 and D2, respectively. The bands are practically located as it is expected from the stripping model. It is concluded that the Ar(+) ion does not collide with the whole hydrogen molecule in a completely inelastic manner as it is the case at low kinetic energies, where the polarization theory of ion-molecule reactions is applicable. The Ar(+) ion interacts only with the captured hydrogen atom without transfer of momentum to the second atom. The critical energies of the incident Ar(+) ions, above which the cross sections of the two reactions are zero, differ by a factor of about 2 and agree with the energies calculated from the stripping model. In addition, some minor deviations from the stripping model are mentioned. (Author).
Download or read book On the Collision Mechanism of Bimolecular Reactions written by K. Lacmann and published by . This book was released on 1968 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: The bands of ArH(+) and ArD(+) ions have been observed in the velocity spectra of the ions resulting from the interaction (chemical reaction and scattering) of Ar(+) ions with H2 and D2, respectively. The bands are practically located as it is expected from the stripping model. It is concluded that the Ar(+) ion does not collide with the whole hydrogen molecule in a completely inelastic manner as it is the case at low kinetic energies, where the polarization theory of ion-molecule reactions is applicable. The Ar(+) ion interacts only with the captured hydrogen atom without transfer of momentum to the second atom. The critical energies of the incident Ar(+) ions, above which the cross sections of the two reactions are zero, differ by a factor of about 2 and agree with the energies calculated from the stripping model. In addition, some minor deviations from the stripping model are mentioned.
Download or read book Technical Abstract Bulletin written by and published by . This book was released on with total page 992 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book On the Collision Mechanism of Bimolecular Reactions Investigations of the reaction N2 H2 D2 right arrow N2H H N2D D and CO H2 D2 right arrow COH H COD D written by A. Henglein and published by . This book was released on 1968 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Bibliography of AFCRL Publications from 1 October to 31 December 1968 written by Air Force Cambridge Research Laboratories (U.S.) and published by . This book was released on 1969 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt: This bibliography lists all AFCRL in-house reports, journal articles, and contractor reports issued from 1 October to 31 December 1968.
Download or read book On the Collision Mechanism of Bimolecular Reactions Part I Theory and Experimental Method for the Determination of the Velocity Spectrum of Products from Simple H Transfer Reactions of the Type X H2 to XH H written by A. Henglein and published by . This book was released on 1968 with total page 25 pages. Available in PDF, EPUB and Kindle. Book excerpt: A simple apparatus is described which allows one to measure the velocity spectrum of the XH(+) or XD(+) ions, respectively, resulting from ion-molecule reactions of the type X(+) + H2(D2) forming XH(+) + H(XD(+) + D). The secondary ions are not accelerated after their formation. The incident X(+)-ions have kinetic energies between 20 and 200 cV. Furthermore, the velocity spectra are calculated which have to be expected for different collision models. (1) Complex model: All the atoms in the reactants participate in the collision. Every kind of collision between those limiting cases is conceivable, in which the relative kinetic energy of the reactants and the heat of reaction appear as internal energy of the product ion or as kinetic energy of both products (completely inelastic and elastic collision with atomic rearrangement, respectively). (2) Stripping model: The incident X(+)-particle hits only one atom of the hydrogen molecule in a completely inelastic collision without transfer of momentum to the second hydrogen atom. It is also shown that the cross section of the reaction becomes zero above a certain energy of the incident ion. This critical energy depends on the collision mechanism. It can be measured with the apparatus described. In addition an isotope effect of the order of 2 with respect to the critical energy is expected from the transfer of an H or D atom, respectively.
Download or read book On the Collision Mechanism of Bimolecular Reactions Theory and experimental method for the determination of the velocity spectrum of products from Simple H transfer reactions of the type X H2 right arrow XH H written by A. Henglein and published by . This book was released on 1968 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book On the Collision Mechanism of Bimolecular Reactions written by A. Henglein and published by . This book was released on 1968 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: A simple apparatus is described which allows one to measure the velocity spectrum of the XH(+) or XD(+) ions, respectively, resulting from ion-molecule reactions of the type X(+) + H2(D2) forming XH(+) + H(XD(+) + D). The secondary ions are not accelerated after their formation. The incident X(+)-ions have kinetic energies between 20 and 200 cV. Furthermore, the velocity spectra are calculated which have to be expected for different collision models. (1) Complex model: All the atoms in the reactants participate in the collision. Every kind of collision between those limiting cases is conceivable, in which the relative kinetic energy of the reactants and the heat of reaction appear as internal energy of the product ion or as kinetic energy of both products (completely inelastic and elastic collision with atomic rearrangement, respectively). (2) Stripping model: The incident X(+)-particle hits only one atom of the hydrogen molecule in a completely inelastic collision without transfer of momentum to the second hydrogen atom. It is also shown that the cross section of the reaction becomes zero above a certain energy of the incident ion. This critical energy depends on the collision mechanism. It can be measured with the apparatus described. In addition an isotope effect of the order of 2 with respect to the critical energy is expected from the transfer of an H or D atom, respectively.
Download or read book On the Collision Mechanism of Biomolecular Reactions Part III Investigations of the Reaction N2 H2 D2 to N2H H N2D D and CO H2 D2 to COH H COD D written by K. Lacmann and published by . This book was released on 1968 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: At moderate kinetic energies up to about 50 eV of the incident ion, the velocity spectra agree with the predictions of the stripping model. At higher energies, the bands of the product ions are shifted to somewhat higher velocities. This indicates preferential forward scattering of the charged reaction product and less conversion of kinetic energy of the incident ion into internal energy of the products. As was expected, the cross sections for the transfer of an H- and D-atom are equal at the same relative kinetic energy. Over a wide range of energy, the cross section depends on the relative kinetic energy as sigma = k1 . c to the ( -k2Es) power. Reactions could still be observed at relative kinetic energies, which are larger than the dissociation energy of the product ion (up to 7 eV for N2H(+) and N2D(+) and up to 10 eV for COH(+) and COD(+)). These details of the collision mechanism are tentatively explained by two hypotheses. (Author).
Download or read book On the Collision Mechanism of Bimolecular Reactions written by K. Lacmann and published by . This book was released on 1968 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book State to state Reaction Dynamics of H D2 and the Alignment and Orientation of Hydrogen Molecules written by Nathaniel Chung-Ming Bartlett and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis details part of the ongoing experimental effort on the investigation of the dynamics of the simplest neutral bimolecular reaction system: H + D2 hydrogen exchange. A combination of molecular beam and laser-based spectroscopic techniques have been used to produce H + D2 collisions under single collision conditions, and the three-dimensional velocity distribution of state-selected HD(v', j') reaction products is captured by ion imaging. HBr and D2 are pre-mixed and co-expanded into high vacuum through a pulsed nozzle. The co-expansion produces rotationally cooled reagents with very little relative translational energy between them. The molecular beam is collimated by a skimmer before being intersected with a narrow-linewidth tunable ultraviolet laser pulse which cleaves the HBr bond, producing nearly monoenergetic H atoms which can then react with D2 molecules. Nascent HD(v', j') is state-selectively ionized via resonance-enhanced multiphoton ionization (REMPI) using radiation from another narrow-linewidth tunable ultraviolet laser pulse. This process takes place within the extraction region of a linear time-of-flight mass spectrometer fitted with an imaging detector. This configuration allows the three-dimensional velocity of individual HD(v', j') products to be recorded. Velocity distributions are analyzed and converted into center-of-mass frame scattering angle distributions or differential cross sections (DCS) using photoloc. Using these methods state-to-state differential cross sections have been measured for H + D2(v'=0, j'=0,1,2) --> HD(v'=2, j'=0,3,6,9) + D for collision energies of Ec = 1.25, 1.61, and 1.97 eV. The DCSs are compared to those calculated by Foudhil Bouakline and Stuart Althorpe after being "blurred" according to our experimental conditions. The measured DCSs are in most cases in good agreement with the calculated ones, and show the expected behavior for this reaction system which takes place via a direct recoil mechanism through a collinear transition state geometry. For a given collision energy, as the HD rotational state increases the DCSs shift from being strongly peaked in the backward scattering region to being peaked toward more sideward angles. For a given HD rotational state, as the collision energy increases the DCSs narrow and become peaked at slightly larger angles. The HD(v'=2, j'=0) state produced from reactive collisions at Ec = 1.25 eV displays unique scattering behavior in that its DCS is bimodal. This suggests that there are two competing mechanisms available for this product at this collision energy. The first is the same direct recoil mechanism responsible for product formation of all other rotational state/collision energy combinations investigated. The second is an indirect mechanism opened by a barrier resonance in which the transition state is able to rotate a fraction of a cycle before breaking apart into products. The dynamics observed here are overall similar to that found in related H + D2(v'=0, j'=0,1,2) --> HD(v'=1,3, j') reactive scattering studies performed by our group. Additionally, in a series of adjacent experiments, stimulated Raman pumping (SRP) with polarized light was used to prepare highly aligned and oriented samples of vibrationally-rotationally excited hydrogen molecules in a molecular beam expansion under collision-free conditions. Of particular significance, the (1,0) S(0) SRP line was used to prepare samples of H2(v=1, j=2, M=0) and H2(v=1, j=2, M=2) using linear or circularly polarized light, respectively. After excitation the degree of alignment was monitored using resonance-enhanced multiphoton ionization also with polarized light. This rotational level is not subject to hyperfine depolarization and we find that the samples produced retain their initial degree of alignment or orientation for up to 8 [Mu]s which makes them quite suitable for serving as aligned targets in H + H2 scattering experiments. The same SRP scheme was also used to produce aligned samples of HD(v=1, j=2, M=0) and D2(v=1, j=2, M=0) as well, both of which undergo hyperfine depolarization, through the coupling of the molecules' rotational angular momentum to the nuclear spin angular momenta. The result is that the degree of alignment becomes an oscillatory function of time, which again can be observed using REMPI. We compare the measured time-dependent alignment with a theoretical calculation for HD(v=0, j=2, M=0) and D2(v=0, j=2, M=0) and find the agreement to be within our experimental error. Thus we conclude that the hyperfine constants do not strongly vary with the vibrational state.
Download or read book Radiation Biophysics written by Edward L. Alpen and published by Academic Press. This book was released on 1997-10-22 with total page 517 pages. Available in PDF, EPUB and Kindle. Book excerpt: This newly revised and updated edition of Radiation Biophysics provides an in-depth description of the physics and chemistry of radiation and its effects on biological systems. Coverage begins with fundamental concepts of the physics of radiation and radioactivity, then progresses through the chemistry and biology of the interaction of radiation with living systems. The Second Edition of this highly praised text includes major revisions which reflect the rapid advances in the field. New material covers recent developments in the fields of carcinogenesis, DNA repair, molecular genetics, and the molecular biology of oncogenes and tumor suppressor genes. The book also includes extensive discussion of the practical impact of radiation on everyday life. Covers the fundamentals of radiation physics in a manner that is understandable to students and professionals with a limited physics background Includes problem sets and exercises to aid both teachers and students Discusses radioactivity, internally deposited radionuclides, and dosimetry Analyzes the risks for occupational and non-occupational workers exposed to radiation sources
Download or read book The Activation of Dioxygen and Homogeneous Catalytic Oxidation written by D.H.R. Barton and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 503 pages. Available in PDF, EPUB and Kindle. Book excerpt: This monograph consists of the proceedings of the Fifth International Symposium on the Activation of Dioxygen and Homogeneous Catalytic Oxidation, held in College Station, Texas, March 14-19, 1993. It contains an introductory chapter authored by Professors D. H. R. Barton and D. T. Sawyer, and twenty-nine chapters describing presentations by the plenary lecturers and invited speakers. One of the invited speakers, who could not submit a manuscript for reasons beyond his control, is represented by an abstract of his lecture. Also included are abstracts of forty-seven posters contributed by participants in the symposium. Readers who may wish to know more about the subjects presented in abstract form are invited to communicate directly with the authors of the abstracts. This is the fifth international symposium that has been held on this subject. The first was hosted by the CNRS, May 21-29, 1979, in Bendor, France (on the Island of Bandol). The second meeting was organized as a NATO workshop in Padova, Italy, June 24-27, 1984. This was followed by a meeting in Tsukuba, Japan, July 12-16, 1987. The fourth symposium was held at Balatonfured, Hungary, September 10-14, 1990. The sixth meeting is scheduled to take place in Delft, The Netherlands (late Spring, 1996); the organizer and host will be Professor R. A. Sheldon.
Download or read book Astrochemistry and Astrobiology written by Ian W. M. Smith and published by Springer Science & Business Media. This book was released on 2012-10-28 with total page 353 pages. Available in PDF, EPUB and Kindle. Book excerpt: Astrochemistry and Astrobiology is the debut volume in the new series Physical Chemistry in Action. Aimed at both the novice and experienced researcher, this volume outlines the physico-chemical principles which underpin our attempts to understand astrochemistry and predict astrobiology. An introductory chapter includes fundamental aspects of physical chemistry required for understanding the field. Eight further chapters address specific topics, encompassing basic theory and models, up-to-date research and an outlook on future work. The last chapter examines each of the topics again but addressed from a different angle. Written and edited by international experts, this text is accessible for those entering the field of astrochemistry and astrobiology, while it still remains interesting for more experienced researchers.
Download or read book Dorland s Dictionary of Medical Acronyms and Abbreviations E Book written by Dorland and published by Elsevier Health Sciences. This book was released on 2015-07-24 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt: Medical acronyms and abbreviations offer convenience, but those countless shortcuts can often be confusing. Now a part of the popular Dorland’s suite of products, this reference features thousands of terms from across various medical specialties. Its alphabetical arrangement makes for quick reference, and expanded coverage of symbols ensures they are easier to find. Effective communication plays an important role in all medical settings, so turn to this trusted volume for nearly any medical abbreviation you might encounter. Symbols section makes it easier to locate unusual or seldom-used symbols. Convenient alphabetical format allows you to find the entry you need more intuitively. More than 90,000 entries and definitions. Many new and updated entries including terminology in expanding specialties, such as Nursing; Physical, Occupational, and Speech Therapies; Transcription and Coding; Computer and Technical Fields. New section on abbreviations to avoid, including Joint Commission abbreviations that are not to be used. Incorporates updates suggested by the Institute for Safe Medication Practices (ISMP).
Download or read book Sulfur Centered Reactive Intermediates in Chemistry and Biology written by C. Chatgilialoglu and published by Springer Science & Business Media. This book was released on 2013-03-08 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt: A wonderfully successful NATO Advanced Study Institute on "Sulfur-Centered Reactive Intermediates in Chemistry and Biology" was held 18-30 June, 1989, at the Hotel Villa del Mare in Maratea, Italy. Despite the beautiful setting with mountains behind us and over looking the clear blue Mediterranean Sea under a cloudless sky (and with a private beach available), the lectures were extremely well attended. While some credit can go to the seriousness of the students, more must go to the calibre of speakers and the high quality of C. Chatgilialoglu, and Co-Director, Professor K. -D. their presentations. The Director, Dr. Asmus, are to be congratulated for putting together such an outstanding scientific program. Dr. Chatgilialoglu is also to be commended for arranging an equally stimulating social pro gram which included bus, train and boat trips to many local sites of interest. It was particularly fitting that a meeting on the chemistry and biochemistry of sulfur should be held in Italy since Italian chemists have made major contributions to our under standing of the organic chemistry of sulfur, including the chemistry of its reactive inter mediates. The early Italian interest in sulfur chemistry arose from the fact that Italy, or more specifically, Sicily, was a major world producer of sulfur prior to the development and exploitation of the Frasch process in Texas and Louisiana.
