Bromine Photodissociation Chemical Laser
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Quantum yields and energy partitioning in the ultraviolet
and intersected by either one or two laser pulses. The bromine atoms were probed using 211 resonance-enhanced multiphoton ionization ~REMPI! transitions in the wavelength region between 233 and 267 nm.12 The tunable laser pulses were generated by a dye laser that was pumped by 355 nm light from the third harmonic of a Nd:YAD laser operating at
Mar 20, 2021 oxygen iodine chemical laser Nikolai P Vagin, P G Kryukov, V S Pazyuk et al.-Search for the composition of the active medium of an HgF laser I S Lakoba-Investigation of a pulsed oxygen iodine chemical laser N F Balan, R M Gizatullin, A V Dubrovski et al.-This content was downloaded from IP address 22.214.171.124 on 20/03/2021 at 01:33
Michael A. Waxman (Vaksman) - UW-Super
Formation of longitudinal particle density gradient in velocity-selective laser photodissociation. Sov. J. Quantum Electron. (USA) 12, #5, pp. 570-573 (1982). 5. A.V. Ghiner and M.A. Vaksman The increase of the longitudinal gradient of particle concentration under velocity-selective photodissociation by laser. Opt. Commun.
Coulomb explosion and dissociative ionization of 1,2
formation or bromine molecular elimination by either a stepwise or a concerted (synchronous or asynchronous) mech-anism may take place in the dissociation process of these molecules.18 20 In the photodissociation studies of 1,1 and 1,2-C 2H 4Br 2 with the ultraviolet (248 nm) laser by product trans-
Photodissociation of Bromoform at 248 nm: Single and
most important photodissociation channel of CHBr3 in the UV region is C-Br bond breaking. I. Introduction The role of anthropogenic chlorine and bromine containing molecules in stratospheric ozone depletion has been well established.1 The importance of bromine and its chemistry on the atmosphere is receiving renewed interest on the basis of
SPECTREX, -I ,. PECKMAN AR 220 L (201) 239-8398 FAX
region, the halocarbons react with the ozone in a series of chemical reactions, causing the ozone's decomposition. Ozone (03) is a trace gas in the earth's atmosphere. It predominates in the stratosphere where it shields the earth's surface from damaging U.V radiation from the sun. Ozone itself undergoes-photodissociation when
FERNANDERS, MARIUM S., M.S. Crossed Molecular Beam Study of X
experimental chamber (located in laboratory chemical hood) 38 Figure 24. Photodissociation OPO laser scan (over part of Hartley band) of ozone at a fixed mm-wave frequency centered on an intense ozone rotational transition (249788.5520 MHz) 40 Figure 25.
Ingle, R. A., Hansen, C. S., Elsdon, E., Bain, M., King, S. J
The Journal of Chemical Physics 147, 013901013901 (2017); 10.1063/1.4973680 Advantage of spatial map ion imaging in the study of large molecule photodissociation The Journal of Chemical Physics 147, 013904013904 (2017); 10.1063/1.4975671 A simple resonance enhanced laser ionization scheme for CO via the A1Π state
Soviet Journal of Quantum Electronics ARTICLES Related
The maximum output energy of a photodissociation chemical laser is 3.9 and 1.6 times higher than the values for photodissociation and chemical lasers, respectively. The degree of excitation of bromine atoms in the second reaction, determined by laser resonance spectroscopy, is £ 5 = [ΒΓ(2Λ /2)]/[ΒΓ(2Λ /2)] + [Br(2/> 3/2)] =0.5 + 0.1. 1
THE KINETICS FOLLOWING PHOTOLYSIS OF NITROSYL BROMIDE
One candidate for the development of a tunable laser in the mid-infrared for use as a defensive countermeasure against passive sensors exploits the nitric oxide (NO) transition at 5.4 µm. However, the difficulty with this mechanism is that when bromine (Br2) and NO are present in a mixture, nitrosyl bromide (BrNO) is also created.
Photodissociation dynamics of CH BrCl studied using resonance
The bromine atoms were probed using 211 resonance-enhanced multiphoton ionization ~REMPI! transitions in the region of 250 270 nm.16 The laser pulses were generated by a LAS-LDL 2051 dye laser using Coumarin 500. The dye laser was pumped by 355 nm light from the third harmonic of a Nd:YAG laser ~Spectra-Physics, GCR-150! operating at 10 Hz.
Spectroscopic And Computational Studies Of The Laser
abundant bromine-containing halon, 10. although it is expected to have a relatively short tropospheric lifetime, on the order of several hundred days. 11. The photochemistry and ultimate atmospheric fate of EDB and related compounds is a topic of current interest. 11. The ultraviolet (UV) photodissociation dynamics of EDB has
From Gas Phase to Bulk Photodissociation of Neutral Size
Velocity map images of H photofragment after photodissociation of HBr molecule a) and large clusters b) at 243nm and appropriate Total Kinetic Energy Released spectra c). Photodissociation laser polarization axis is in vertical direction of image plane. a) b) c) 162
Dissociation Channels of the 1-Propenyl Radical and Its
Chemical Sciences DiVision, Lawrence Berkeley National Laboratory, Berkeley, California 94720 ReceiVed: February 1, 2002 The primary photodissociation dynamics of cis-1-bromopropene upon excitation at 193 nm and the unimolecular dissociation dynamics of the nascent 1-propenyl radical are investigated in a crossed laser-molecular beam apparatus.
Time resolved photoelectron spectroscopy with ultrafast soft
1.8 A classical picture of high-order harmonic generation with an ultrafast laser. The coulomb potential of the atom is perturbed in the presence of the strong laser ﬁeld, and tunneling ionization of the electron occurs. The free electron gains energy in the electric ﬁeld (U p, pondoromotive potential). As the optical
Further Studies into the Photodissociation Pathways of 2
the new data obtained with a crossed-laser molecular beam scattering apparatus with VUV photoionization detection at Taiwan s National Synchrotron Radiation Research Center (NSRRC) and new velocity map imaging data better characterize two of the four primary 193 nm photodissociation channels. The C−Br photoﬁssion channel forming the 2-
Leone, Stephen Publications from website
S. R. Leone and F. J. Wodarczyk, Laser excited electronic-to-vibrational energy transfer from Br(4 2 P 1/2 ) to HCl and HBr , J. Chem. Phys. 60 , 314 (1974).
photodissociation laser. A major experi-mental problem that will have to be re-solved is balancing the efficiency ofdetect-ing a beryllium atom and the reduction of scattered light. If the entrance and exit windowswere closed to the region that the phototube images, there wouldbescattered light produced as the dye laser beampasses through (in
Structures of bromoalkanes photodissociation in solution by
(picosecond laser pulse coincided with nanosecond x-ray pulse), and no structure kinetics have been measured so far by these investigators. In our earlier papers (8, 28, 29) the bromine K edge (13.5 keV) EXAFS spectra of initial and final products of carbon tetrabromide (CBr4) photodissociation in ethanol solution have
Photodissociation study of CH Br in the ﬁrst continuum
Photodissociation via excitation to the A band ~ﬁrst con-tinuum! produces ground state, Br(2P 3/2), and spin orbit ex-cited, Br(2P 1/2), bromine atoms that we label as Br and Br*, respectively. Bromine atoms are known to be 40 times more efﬁcient than chlorine atoms in breaking down the atmo-spheric ozone.2 Recent studies have indicated
4 Photodissociation in the gas phase
Photodissociation dynamics concerns the mechanisms of photodissociation reactions investigated in atomistic detail, tracing the time evolution of every microscopic step, as far as possible. The main motive of such research is to clarify the true nature of the chemical reactions. The photodissociation reaction photoexcited molecules A
Chemistry, Dynamics, and Radiation of Ozone Airborne
chlorine (left) and bromine (right). W Bromine Calibration Calibration of the bromine detection system takes advantage of our well-established chlorine atom calibration. Specifically, a known, constant flow of C1 is titrated with excess Br2 to generate a quantitative Br source. C1+ Br2 + BrCl +Br k = 1.6~10-10 cm3 molec-1 s-I
Br2 molecular elimination in 248 nm photolysis of CHBr2Cl by
Elimination of molecular bromine is probed in the B 3 ou + ←X 1 g + transition following photodissociation of CHBr 2Cl at 248 nm by using cavity ring-down absorption spectroscopy. The quantum yield for the Br 2 elimination reaction is determined to be 0.05±0.03. The nascent vibrational population ratio of Br 2 v=1 /Br
Photodissociation Dynamics of the Cyclohexyl Radical from the
Mar 16, 2021 ABSTRACT: The photodissociation of jet-cooled cyclohexyl was studied by exciting the radicals to their 3p Rydberg state by using 248 nm laser light and detecting photoproducts by photofragment translational spectroscopy. Both H atom loss and dissociation to heavy fragment pairs are observed. The H atom loss channel
FINAL TECHNICAL REPORT: EXPERIMENTAL AND COMPUTER MODELING
The second, ultraviolet, laser photon is not by itself isotopically selective, but photodissociates vibrationally excited molecules more efficiently than ground state molecules, producing isotopic enrichment in the photodissociation fragments. Subsequent chemical scavenging reactions provide the means for collecting the
Pandit, S., Preston, T. J., King, S. J., Vallance, C., & Orr
Photodissociation of gaseous bromocyclopropane via its A-band continuum has been studied at excitation wavelengths ranging from 230 nm to 267 nm. Velocity-map images of ground-state bromine atoms (Br), spin-orbit excited bromine atoms (Br*) and C 3 H 5 hydrocarbon radicals reveal the kinetic energies of these various photofragments.
Theoretical investigations of a space-based, Br (4 2P 4 2P
In the interest of exploring the feasibility of a low-maintenance, space-based laser, a kinetic model of the directly solar-pumped, atomic bromine laser (operating on the Br (4 2P 1/2→ 2P 3/2) transition under IBr photolysis) was developed, executed, and interpreted. A set of nonlinear differential equations
Molecular elimination of Br2 in 248 nm photolysis of
the nascent vibrational spectra of the molecular bromine fragmented in the photodissociation of bromoform. An exci-mer laser at 248 nm is employed to dissociate bromoform in a ring-down cell, while the other tunable laser is used to probe the Br2 fragment. Given the absorbed photon number density and the Br2 concentration produced in the beam-
Photodissociation Dynamics of C F Br at 234 nm: Fluorination
Photodissociation Dynamics of C6F5Br at 234 nm: Fluorination Effects on Br/Br* Formation Pathways Dababrata Paul, Hyun Kook Kim, and Tae Kyu Kim * Department of Chemistry and Chemical Institute for Functional Materials, Pusan National University, Busan 609-735, Korea *E-mail: [email protected] Received November 21, 2012, Accepted December 9, 2012
Durham Research Online - CORE
The production of a translationally cold (T < 1 K) sample of bromine atoms with estimated densities of up to 108 cm−3 using photodissociation is presented. A molecular beam of Br 2 seeded in Kr is photodissociated into Br + Br* fragments, and the
Photodissociation of CBrCl at 234 and 265 nm: Evidence of the
by the UV laser light and bromine atom fragments were then selectively ionized at 233.9 and 264.8 nm for Br*, and at 233.6 and 264.9 nm for Br using the @211# REMPI technique22 within the same laser pulse. The laser was scanned over a range of 4 cm21 in order to detect all velocity component of bromine fragments.
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Chemical lasers Photochemistry Chemical reactions Photolysis 2 T RACT (C4ninue do reverse side if nceaeay aid Identify by blee. mnubr) The work described here involved the study of halogen atom production and removal following photodissociation of halogens, pseudohalogens and halides. Both collisional quenching and chemical reaction were seen.
Photodissociation of CF3Br at 193 nm: evidence for a
ELSEVIER Chemical Physics 204 (1996) 135-145 Chemical Physics Photodissociation of CF3Br at 193 nm: evidence for a distorted dissociation pathway M.-A. Thelen, P. Felder * Physikalisch-Chemisches lnstitut der Universitfit Z~rich, Winterthurerstrasse 190, CH-8057 Z~rich, Switzerland Received 18 September 1995 Abstract
atmospheric ozone budget
bromine through photodissociation in the stratosphere. In the marine boundary layer, it has been suggested (e.g. Fan and Jacob, 1992; Vogt et al, 1996; Borken and Platt, 1997) that the HOBr conversion into active bromine could occur on aerosol. HOBr would be converted into photolabile BrC1 or Br2 on sea salt, sulfuric acid or ice particles.
temperature Ullmann coupling On-surface photo-dissociation
Figure SI7. The continuous wave laser source at 405 nm (Roithner Laser Technik, GmbH; model X40LM-10, Vienna, Austria) provided a surface power density of 75 mW/cm2 and the sample was illuminated at RT for ≈12 h. In order to exclude any influence of the laser irradiation in the non-illuminated area, i.e. spurious
photoionization and photodissociation dynamics in intense laser field have been an active field of research. By now, many researchers have focused their energies on the simple and small alkyl bromides, such as CH 3Br, 10~12 CH 2Br 2, 13 CF 2Br 2, 14 and CHBr 3. 15,16 However, studies on photoionization and photodissociation of the long-chained
Photodissociation Dynamics Laurie J. Butler* Department of Chemistry, UniVersity of Chicago, Chicago, Illinois 60637 Daniel M. Neumark* Department of Chemistry, UniVersity of California, Berkeley, California 94720, and Chemical Sciences
Subpicosecond resolution studies of the H+CO2 CO+OH reaction
the main chemical effect in photoinitiating the reaction within the complex is steric; i.e., there is no sign&ant propensity for carbon-bromine bonding for either the A or A orientation of the unpaired halogen orbital. These ob- servations suggest that reaction proceeds through the