| Kinetics of the Reactions of ONOO(-) with Small Molecules |
SEP 2006 |
7 pages |
| Authors:
A. A. Viggiano; Anthony J. Midey; A. Ehlerding; AIR FORCE RESEARCH LAB HANSCOM AFB MA SPACE VEHICLES DIRECTORATE
|
 | Rate constants and product distributions have been measured for a number of simple molecules reacting with ONOO(-) at 200 and 300K. NO, CO, H2, CH4, N2O, and H2O did not react with ONOO(-). HCl and HCN underwent proton transfer in addition to other competing channels. Charge transfer from ONOO(-) was observed exclusively with O3 and NO2. SO2 and HCl underwent exchange for NO in ONOO(-). HCN was the only substance ... |
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| Ion chemistry of NOO+ |
21 MAR 2006 |
9 pages |
| Authors:
A. J. Midey; A. I. Fernandez; A. A. Viggiano; P. Zhang; K. Morokuma; AIR FORCE RESEARCH LAB HANSCOM AFB MA SPACE VEHICLES DIRECTORATE
|
| The kinetics for the reactions of NOO(+) ions with neutral molecules having ionization potentials (IPs) from 9.27 to 15.58 eV was measured in a selected ion flow tube at 298 K. The NOO+ ions are produced from the reaction of N3++ 02 and have been reacted with the following: NO, C6F6, CS2, CF3I, C3F6, OCS, C2H6, Xe, S02, 03, N2O, CO2, Kr, CO, D2, and N2. Numerous types of reactions ... |
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| The Study of State-Selected Ion-Molecule Reactions using the Vacuum Ultraviolet Pulsed Field Ionization-Photoion Technique |
2006 |
15 pages |
| Authors:
Rainer A. Dressler; Y. Chiu; D. J. Levandier; X. N. Tang; Y. Hou; C. Chang; C. Houchins; H. Xu; Cheuk-Yiu Ng; AIR FORCE RESEARCH LAB HANSCOM AFB MA SPACE VEHICLES DIRECTORATE
|
| This paper presents the methodology to generate beams of ions in single quantum states for bimolecular ion-molecule reaction dynamics studies using pulsed field ionization (PFI) of atoms or molecules in high-n Rydberg states produced by vacuum ultraviolet (VUV) synchrotron or laser photoexcitation. Employing the pseudocontinuum high-resolution VUV synchrotron radiation at the Advanced Light Source as the photoionization source, PFI photoions (PFI-PIs) in selected rovibrational states have been generated for ion-molecule ... |
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| Collisional Stabilization of Highly Vibrationally Excited Omicron-, Mu- and Rho-Xylene Ions (C8H10+) from 300-900 K and 1-250 Torr |
2006 |
7 pages |
| Authors:
AIR FORCE RESEARCH LAB HANSCOM AFB MA SPACE VEHICLES DIRECTORATE
|
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| Ion-Molecule Kinetics at 15-700 Torr |
2005 |
8 pages |
| Authors:
A. A. Viggiano; Abel I. Fernandez; J. Troe; AIR FORCE RESEARCH LAB HANSCOM AFB MA SPACE VEHICLES DIRECTORATE
|
| Studies of ion-molecule chemistry are usually made at pressures of a few Torr and below. By contrast, there are numerous plasmas that occur at higher pressures. For that reason, we have constructed a turbulent ion flow tube (TIFT) for studying ion-molecule kinetics from 15 to 700 Torr. Currently, the TIFT operates from room temperature to 700 K. Here we present a summary of the measurements we have made to date. ... |
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| Dissociative Recombination Study of Na(+) (D2O) in a Storage Ring |
01 DEC 2004 |
7 pages |
| Authors:
Vitali Zhaunerchyk; Anneli Ehlerding; Wolf D. Geppert; Fredrik Hellberg; Richard D. Thomas; Mats Larsson; Albert A. Viggiano; Susan T. Arnold; Fabian Oesterdahl; STOCKHOLM UNIV (SWEDEN) INST OF PHYSICS
|
| The dissociative recombination of Na(+) (D2O) ion has been studied at the heavy-ion storage ring CRYRING (Manne Siegbahn Laboratory, Stockholm University). The cross section has been measured as a function of center-of-mass energy ranging from 1 meV to 0.1 eV and found to have an E (sup -1.37) dependence. The rate coefficient has been deduced to be (2.3 +/- 0.32) X 10(exp -7) x T(sub e/300)(exp -0.95 +/- 0.01)cu cm ... |
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| Ion-Molecule Rate Constants and Branching Ratios for the Reaction of N(3)+ + O(2) From 120 to 1400 K |
15 NOV 2004 |
9 pages |
| Authors:
Svetozar Popovic; Anthony J. Midey; Skip Williams; Abel I. Fernandez; A. A. Viggiano; Peng Zhang; K. Morokuma; AIR FORCE RESEARCH LAB HANSCOM AFB MA SPACE VEHICLES DIRECTORATE
|
| The kinetics of the reaction of N3(+) with O2 has been studied from 120 to 1400 K using both a selected ion flow tube and high-temperature flowing afterglow. The rate constant decreases from 120 K to approx. 1200 K and then increases slightly up to the maximum temperature studied, 1400 K. The rate constant compares well to most of the previous measurements in the overlapping temperature range. Comparing the results ... |
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| Reactions of N(+), N2(+), and N3(+) with NO From 300 to 1400 K |
08 OCT 2004 |
9 pages |
| Authors:
Anthony J. Midey; Thomas M. Miller; A. A. Viggiano; AIR FORCE RESEARCH LAB HANSCOM AFB MA SPACE VEHICLES DIRECTORATE
|
| Rate constants have been measured from 300 to 1400 K in a selected ion flow tube (SIFT) and a high temperature flowing afterglow for the reactions of N(+), N2(+) and N3(+) with NO. In all of the systems, the rate constants are substantially less than the collision rate constant. Comparing the high temperature results to kinetics studies as a function of translational energy show that all types of energy (translational, ... |
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| Reaction Kinetics of PO2Cl(-), PO2Cl2(-), POCl2(-), and POCl3(-) with O2 and O3 from 163 to 400 K |
28 SEP 2004 |
7 pages |
| Authors:
Abel I. Fernandez; Anthony J. Midey; Thomas M. Miller; A. A. Viggiano; AIR FORCE RESEARCH LAB HANSCOM AFB MA SPACE VEHICLES DIRECTORATE
|
| Rate constants and product branching ratios for the gas-phase reactions of O2 and O3 with the anions (a) PO2Cl-, (b)POCl3(-) (c) POCl2(-), and (d) PO2Cl2(-) were measured in a selected ion flow tube. The kinetics were measured at temperatures of 163-400 K and a He pressure of 0.4 Torr. Only PO2Cl(-) reacts with O2 to a measureable extent, having k(163-400 K) = 1.1 x 10(exp -8)(T/K)(exp -1.0)cu cm/molecule/s, while O3 ... |
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| Hyperthermal Reactions of O+(4S3/2) with CD4 and CH4: Theory and Experiment |
24 JUL 2004 |
13 pages |
| Authors:
Dale J. Levandier; Yu-Hui Chiu; Rainer A. Dressler; Lipeng Sun; George C. Schatz; AIR FORCE RESEARCH LAB HANSCOM AFB MA SPACE VEHICLES DIRECTORATE
|
| Theoretical and experimental methods are applied to the study of the reaction dynamics in hyperthermal collisions of 0+(4S3/2) with methane. Measurements of the absolute reaction cross sections for the interaction of 0+ with CD4 and CH4 were obtained at collision energies in the range from near-thermal to approximately 15 eV, using the guided-ion beam (GIB) technique. Product recoil velocity distributions, using the GIB time-of-flight (TOF) methods, were determined for several ... |
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| Theoretical Studies of Gas Phase Elementary Reactions |
04 JUN 2004 |
21 pages |
| Authors:
Keiji Morokuma; EMORY UNIV ATLANTA GA DEPT OF CHEMISTRY
|
| This final technical report begins with the objective the project, followed by detailed technical reports on the new accomplishments and findings obtained in the project. They are presented in three sections: A) Potential Energy Surfaces of Ion-Molecule Reactions; B) Potential Energy Surfaces for Photochemical Reactions and Nonadiabatic Processes; and C) Other Elementary Reactions. The Publication List and Interactions/Transactions conclude the report. |
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| Reactions and Thermochemistry of Alkyl Ions, Cn H2n+1 + (n=1-8), in the Gas Phase |
20 OCT 2003 |
26 pages |
| Authors:
Skip Williams; Thomas M. Miller; W. B. Knighton; Anthony J. Midey; Susan T. Arnold; A. A. Viggiano; Campbell D. Carter; AIR FORCE RESEARCH LAB HANSCOM AFB MA SPACE VEHICLES DIRECTORATE
|
| Our research program focuses on identifying reaction processes important for plasma enhancement of combustion systems. Recommendations for temperature and energy dependencies of key ion-molecule reactions are made based on the laboratory measurements described above. Thermodynamic data such as heat capacity entropy, and enthalpy are not available as a function of temperature for many of the ionic species formed in these reactions and are thus calculated using quantum mechanical methods. The ... |
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| Oxidation of Alkyl Ions, CnH2n+1+ (n=1-5) in Reactions with O2 and O3 in the Gas Phase |
24 SEP 2003 |
11 pages |
| Authors:
Skip Williams; W. B. Knighton; Anthony J. Midley; A. A. Viggiano; Stephen Irle; AIR FORCE RESEARCH LAB HANSCOM AFB MA SPACE VEHICLES DIRECTORATE
|
| Rate constants and product ion branching fractions are reported for the reactions of CH3(+), C2H5(+), s-C3H7(+), s-C4H9(+), t-C4H9(+), and t- C3H11(+) with O2 and O3 at 300 K in a variable-temperature selected-ion flow tube (VT-SIFT). The reaction rate constant for CH3(+) with O3 is large and approximately equal to the thermal energy capture rate constant given by the Su- Chesnavich equation. The C2H5+, s-C3H7(+), and s-C4H9(+) ions are somewhat less ... |
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| Absolute Cross Sections for Collision-Induced Dissociation Reactions of Highly Vibrationally Excited O2(+)(X(sup 2) PI (sub 3/2,1/2g) and a(4) PI (sub 5/2,3/2,1/2,-1/2u) Ions |
DEC 2002 |
8 pages |
| Authors:
Cheuk-Yiu Ng; Rainer A. Dressler; CALIFORNIA UNIV DAVIS DEPT OF CHEMISTRY
|
| During the past funding cycle, we have constructed and successfully integrated a state-of-the-art guided-ion beam mass spectrometer into the high- resolution photoion-photoelectron apparatus (Endstation 2) of the Chemical Dynamics Beamline at the Advanced Light Source (ALS) for the study of ion- molecule reaction dynamics. Preliminary tests on the performance of this guided- ion beam mass spectrometer have been made, indicating that the apparatus is performing well. Using this apparatus, we ... |
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| Reactivity of Highly Excited Diatomic Ions in Hypersonic Nonequilibrium Flow Conditions |
23 OCT 2002 |
17 pages |
| Authors:
Cheuk-Yiu Ng; Rainer A. Dressler; IOWA STATE UNIV AMES DEPT OF CHEMISTRY
|
| During this funding cycle, we have constructed and successfully integrated a state-of-the-art guided-ion beam mass spectrometer into the high- resolution photoion-photoelectron apparatus (Endstation 2) of the Chemical Dynamics Beamline at the Advanced Light Source (ALS) for the study of ion- molecule reaction dynamics. Preliminary tests on the performance of this guided- ion beam mass spectrometer have been made, indicating that the ion-molecule reactio photoionization apparatus is performing well. We have ... |
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| Microwave Cavity Spectroscopy |
26 FEB 2001 |
8 pages |
| Authors:
Richard N. Zare; STANFORD UNIV CA DEPT OF CHEMISTRY
|
| The influence of vibrational and collision energy on ion-molecule reactions was investigated by measuring the cross sections for reactions of NH3(+) created with varying degrees of excitation in the umbrella bending and symmetric stretching modes. Under these conditions, the three major product channels for the NH3(+)/CD3NH2(+) system are CD3NH2(+), CD2=NH2(+) and CD3NH3(+) . Two minor product channels correspond to NH3D(+) and NH4(+). This reaction is found to be mode selective ... |
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| Ion-Molecular Reactions With Organic and Atmospheric Compounds from 150- 1400K |
JUN 2000 |
28 pages |
| Authors:
Anthony Midey; NORTHEAST CONSORTIUM FOR ENGINEERING EDUCATION PORT ROYAL VA
|
| A variable temperature-selected ion flow drift tube (VT-SIFDT) and a high temperature flowing afterglow (HTFA) have been used to study ion-molecule reactions in the 220 - 1400 K temperature range. The effects of electronic, vibrational, and rotational energy on the kinetics of a wide range of reactions important in combustion chemistry have been investigated. |
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| Mimicing Charged Particle-Atom Collisions Using Half-Cycle Electromagnetic Pulses |
14 JAN 2000 |
4 pages |
| Authors:
Robert R. Jones; VIRGINIA UNIV CHARLOTTESVILLE DEPT OF PHYSICS
|
| The research supported by this grant revealed the following important results. The development and demonstration of the Impulsive Momentum Retrieval (IMR) method for directly viewing the momentum distribution of electrons within atoms. The development and demonstration of a "single-shot delay imaging detector that allows us to view electron dynamics in quasi-real time. Measurement of atomic ionization probability in full mock-collision field, including both longitudinal ... |
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| Chemical Processes in the Space Environment |
29 JUL 1999 |
117 pages |
| Authors:
Skip Williams; Dale J. Levandier; ORION INTERNATIONAL TECHNOLOGIES INC ALBUQUERQUE NM
|
| The present report discusses a series of ion-neutral collision experiments conducted in direct collaboration between Orion researchers and USAF customer affiliated sequentially with: PL/WSSI, PL/GPID, PL/GPOS, AFRL/VSBM, AFRL/VSBS. The work addresses hyperthermal chemical processes of importance in the space environment. The reaction between ionospheric ions and water were studied in detail as to the potential source of infrared radiation and ionospheric holes. New experiments were ... |
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| Air Plasma Ion Reactions With Acetylene, Benzene and Naphthalene from 298-1400K |
22 JUN 1999 |
28 pages |
| Authors:
Anthony Midey; NORTHEAST CONSORTIUM FOR ENGINEERING EDUCATION PORT ROYAL VA
|
| A variable temperature-selected ion flow drift tube (VT-SIFDT) and a high temperature flowing afterglow (HTFA) have been used to study ion-molecule reactions in the 163 - 1400 K temperature range. The effects of electronic, vibrational and rotational energy on the kinetics of a wide range of reactions important in combustion chemistry have been investigated. |
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| State-Resolved Reaction Dynamics |
31 JUL 1998 |
9 pages |
| Authors:
Richard N. Zare; STANFORD UNIV CA DEPT OF CHEMISTRY
|
| Reactions of state-selected ammonia cation with D2, D2O, and CD4 were studied using a guided-ion beam instrument. The influence of vibrational and collision energy on these reactions was investigated by measuring cross sections for reaction of (NH3)(+) created with varying degrees of excitation in the umbrella bending- and symmetric stretching-modes. A comparison of the product cross sections from (NH3)(+) created in two states of nearly identical internal ... |
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| State Resolved Dynamics of Ion-Molecule Processes |
16 FEB 98 |
18 pages |
| Authors:
Stephen R. Leone; Veronica M. Bierbaum; COLORADO UNIV AT BOULDER
|
| Flow-drift and selected ion flow tube techniques have been coupled with laser induced fluorescence detection to explore the chemistry and dynamics of gas phase ion molecule interactions. The charge transfer and atom abstraction rates of vibrationally excited ions have been studied, as well as the competition between deactivation and reaction. The reactions and energy transfer of the vibrationally excited molecular nitrogen cation with the rare gases and several diatomic molecules ... |
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| Gas Phase Studies of Boron, Silicon, and Aluminum -- Relationship to Carbon-Carbon Composition |
27 JUN 95 |
24 pages |
| Authors:
R. Damrauer; V. M. Bierbaum; M. S. Gordon; M. Krempp; M. Stephan; COLORADO UNIV AT DENVER
|
| Work on a number of boron hydride anions and cations has been carried out using the unique features of flowing afterglow-selected ion flow tube (FA- SIFF) technology. Reaction of strong base with diborane has allowed the preparation of a number of anionic boron hydride clusters. Many of these including B2H3- have been examined in terms of their reaction chemistry (FA- SIFF) and structure (ah initio computation). The fundamental thermodynamic property ... |
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| Mass Spectrometric Studies of Clusters and Surfaces |
29 AUG 94 |
14 pages |
| Authors:
John R. Eyler; FLORIDA UNIV GAINESVILLE DEPT OF CHEMISTRY
|
| Fourier transform ion cyclotron resonance (FTICR) mass spectrometry was used to obtain information about the reactivity and physical properties of gaseous cluster ions, and to develop various mass spectrometric surface and bulk analysis techniques. New values for electron affinities and ionization potentials of many different semiconductor clusters were determined. Ultra-high resolution glow discharge FTICR mass spectrometry was developed to better characterize solid materials. (Author) |
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| Rate Enhancement of the Reaction of HCl with ClONO2 by Ions: Implications for the Mechanisms of Stratospherically Important Heterogeneous Reactions |
19 AUG 1994 |
3 pages |
| Authors:
Jane M. Van Doren; A. A. Viggiano; Robert A. Morris; PHILLIPS LAB HANSCOM AFB MA
|
| We report the first observation of the ion-assisted neutral reaction of HCl with ClONO2. These two species react efficiently in the gas phase to form nitric acid and chlorine when one or the other is clustered to an NO3(-) core ion. Utilizing a selected ion flow tube we find that reaction 1 proceeds with a rate coefficient of 1.8 x 10(exp -9) cu cm/s at 233 K and that reaction ... |
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| Time-Integrated Optical Emission Studies of Plumes Generated from Laser Ablated Germania Glass |
01 AUG 1994 |
7 pages |
| Authors:
Paul J. Wolf; FRANK J SEILER RESEARCH LAB UNITED STATES AIR FORCE ACADEMY CO
|
| The optical emission from plumes induced by ArF laser irradiation of GeO2 was characterized as a function of laser fluence, distance from the target surface, and ambient O2 pressure. Dispersion of the light emitted by the plume in a vacuum revealed emission from both neutral and singly ionized Ge atoms as well as neutral O atoms. The spatial variation showed that the ion concentration decreased exponentially from the target surface ... |
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| Ion-Molecular Spiraling Collisions and Termolecular Recombination |
AUG 94 |
|
| Authors:
X. Qi; GEORGIA INST OF TECH ATLANTA SCHOOL OF PHYSICS
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 | A modification is made to the semiclassical adiabatic invariance method for ion-dipole and ion-quadrupole capture collisions. This modification to the adiabatic invariance method includes the effects of coupling of the rotational angular momentum of the target molecule with the orbital angular momentum of the projectile ion. The adiabatic potential energies, cross sections and rate coefficients for capture into rotational eigenstates /J, m > of the target molecule, as well as ... |
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| Ion-Molecule Collisions, Electron Molecule Collisions, Excitation and Ionization of Atoms |
08 JUL 94 |
26 pages |
| Authors:
Kenneth L. Bell; Robert H. Reid; QUEEN'S UNIV BELFAST (NORTHERN IRELAND) DEPT OF APPLIED MATHEMATICS AND THEOR ETICAL PHYSICS
|
| Corrected values of the dissociative recombination rate coefficient for N2(+)(v) have been deduced from an analysis of published experimental data. The theory of the dissociative recombination of polyatomic ions has been developed with particular reference to the branching ratios of the exothermic channels. The role of single-electron transitions in dissociative recombination has been discussed and it has been shown that the radiationless transition probability is indeed very high. Research on ... |
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| Effects of Rotational, Vibrational, and Translational Energy on the Rate Constants for the Isotope Exchange Reactions of OH(-) + Dsub2 and OD(-) + Hsub2 |
15 FEB 1994 |
8 pages |
| Authors:
A. A. Viggiano; Robert A. Morris; PHILLIPS LAB HANSCOM AFB MA
|
| Rate constants for the isotope exchange reactions of OH(-) with D sub 2 and OD(-) with H sub 2 have been measured as a function of average center-of- mass kinetic energy at several temperatures. The reaction of OH(-) with D sub 2 is slightly exothermic, and the rate constant has a negative temperature dependence. The kinetic energy dependences of the rate constants have minima near 0.1 eV. A strong negative ... |
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| Ion-Molecule Chemistry Related to Plasma Deposition and Etching of Silicon |
FEB 94 |
20 pages |
| Authors:
Peter B. Armentrout; UTAH UNIV SALT LAKE CITY DEPT OF CHEMISTRY
|
| During the 5 years of this contract, we used guided ion beam tandem mass spectrometric methods to study a variety of gas-phase ion-molecule reactions relevant to plasma deposition and etching of silicon. Absolute cross sections over a wide range of kinetic energies for reactions involving both atomic and polyatomic ions were measured. The results yielded energy dependent cross sections, temperature dependent rate constants, and thermochemical data, information vital to further ... |
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| Thermal Decomposition of Hsub3O(-) Produced in Reaction of OH(-) with Hsub2CO |
01 JAN 1994 |
7 pages |
| Authors:
A. A. Viggiano; Thomas M. Miller; Amy E. Miller; Robert A. Morris; John F. Paulson; Eileen R. Brown; Emmett A. Sutton; PHILLIPS LAB HANSCOM AFB MA
|
| The ion-molecule reaction OH(-) + Hsub2CO yields Hsub3O(-) + CO has been studied at 300 K with isotopic labeling of reactants. The Hsub3O(-) product is only observed in small abundance because the ion dissociates into OH(-) + Hsub2 upon multiple collisions in a helium buffer gas. Without isotopic labeling, the pseudo-first-order kinetics plots for the reactions of OH(-) with Hsub2CO and OD(-) + Dsub2CO were found to be curved as ... |
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| Ion-Molecule Reactions at Very High Temperatures |
1994 |
5 pages |
| Authors:
PHILLIPS LAB HANSCOM AFB MA
|
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| Guided-Ion Beam Measurements of the Kr(+) + NO Charge-Transfer Reaction |
17 DEC 1993 |
9 pages |
| Authors:
Rainer A. Dressler; Skip Williams; Susan T. Graul; Richard H. Salter; Edmond Murad; PHILLIPS LAB HANSCOM AFB MA
|
| Guided-ion beam measurements of Kr(+) + NO charge-transfer reaction cross sections are presented over a collision energy range of 0.08 to 16 eV (c. m.). At energies below 2 eV, the charge-transfer cross section is approximately two orders of magnitude smaller than the Langevin capture cross section and decreases with collision energy displaying an EsubT(-0.4) dependence. The cross section reaches a minimum at about 3 eV, increases with collision energy ... |
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| Guided-Ion Beam Measurements of the X(+) + Hsub2O(Dsub2O) (X = Ar, Nsub2) Collision Systems |
15 JUL 1993 |
15 pages |
| Authors:
Rainer A. Dressler; Richard H. Salter; Edmond Murad; PHILLIPS LAB HANSCOM AFB MA
|
| Guided-ion beam cross section and product kinetic energy measurements of charge-transfer and atom-abstraction reactions of the Ar(+) + Hsub2O(Dsub2O) and Nsub2(+) + Hsub2O(Dsub2O) collision systems are presented for collision energies ranging between 0.2 and 20 eV c.m. Both charge-transfer systems exhibit large hyperthermal cross sections exceeding 10 A(2) and are characterized by a long-range interaction, evidenced by the small amount of angular scattering observed in product-ion time-of-flight (TOF) measurements. Weak ... |
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| Cathode Sheath Charge Transfer Effects |
MAR 93 |
126 pages |
| Authors:
H. H. Michels; R. H. Hobbs; UNITED TECHNOLOGIES RESEARCH CENTER EAST HARTFORD CT
|
| The United Technologies Research Center, under Contract No. F33615- 87-C-2718, has carried out a theoretical research investigation of ion-molecule reactions that take place in the sheath region of low pressure discharges in silane gas mixtures. Of particular interest were the dissociative charge transfer mechanism(s) and energy dependent reaction rates of electrons, H+, H-, H3+ and several noble gas ions (He+, Ne+, Ar+) in collisions with silane (SiH4). Such reactions are ... |
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| Modeling Study to Evaluate the Ionic Mechanism of Soot Formation in Flames |
FEB 93 |
37 pages |
| Authors:
H. F. Calcote; R. J. Gill; D. G. Keil; AEROCHEM RESEARCH LABS INC PRINCETON NJ
|
| A study is underway to evaluate the proposed ionic mechanism of soot formation by developing a computer model and comparing it with experimental results and with equivalent models based on neutral species. During the present report period both the thermodynamic and reaction kinetic dat base for ion- molecule reactions have been updated and expanded. The CHEMKIN-II flame code, revised last report period, to handle ions is now operating routinely and ... |
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| Collisional Energy Transfer in Biomolecular Ion- Molecule Dynamics |
25 JAN 93 |
50 pages |
| Authors:
Maciej Gutowski; Mark Roberson; Jon Ru; Jack Simons Ii; UTAH UNIV SALT LAKE CITY DEPT OF CHEMISTRY
|
| Guided ion beam kinetic energy thresholds in the ion-molecule reactions M(+) + H2 yields M H(+) + H where M(+) = B(+), Al(+), and Ga(+) exceed by 0.4 to ca. 5 eV the thermodynamic energy requirements or theoretically computed barrier heights of these reactions. In addition, the formation of MD(+) occurs at a significantly lower threshold than MH(+) when M(+) reacts with HD. Moreover, the measured reaction cross sections for ... |
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| Theoretical Treatment of Spin-Forbidden and Electronically Nonadiabatic Processes. Methods and Applications |
10 JAN 93 |
23 pages |
| Authors:
David R. Yarkony; JOHNS HOPKINS UNIV BALTIMORE MD DEPT OF CHEMISTRY
|
| This research program focusses on the electronic structure aspects of radiationless decay processes related to the stability and formation of high energy density materials. We have also begun theoretical studies on electronic nonadiabaticity in ion-molecule reactions. These studies are enabled by a unique system of electronic structure algorithms, the BROOKLYN programs, which we have developed over the last decade. These programs provide advanced capabilities for the study of the electronic ... |
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| Reactivity of the Radical Anion OCC(-) |
1993 |
9 pages |
| Authors:
Jane M. Van Doren; Thomas M. Miller; Amy E. Miller; A. A. Viggiano; Robert A. Morris; John F. Paulson; PHILLIPS LAB HANSCOM AFB MA
|
| The characteristic reactivity of the radical anion OCC(-) has been investigated in the gas phase at 298 K through determination of rate coefficients, products, and branching fractions for each of 29 ion-molecule reactions. A wide variety of reactions is observed including abstraction of H, H(+), and Hsub2(+), nucleophilic displacement, charge transfer, and reactions involving electron detachment. Many of the reactions involve cleavage of the C(- )-CO bond, consistent with the ... |
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| OH Alpha 2Sigma(+) Yields Chi 2Pi Chemiluminescence Measurements of Nsub2(+), Ar(+) + Hsub2O Hydrogen-Atom-Transfer Reactions at Suprathermal Energies |
15 AUG 1992 |
10 pages |
| Authors:
James A. Gardner; Rainer A. Dressler; Richard H. Salter; Edmond Murad; PHILLIPS LAB HANSCOM AFB MA
|
| Chemiluminescence attributable to OH Alpha 2Sigma(+) yields Chi 2Pi emission is observed in hydrogen-atom transfer reactions of Nsub2(+) and Ar(+) with Hsub2O. High-resolution OH Alpha yields Chi spectra (0.5 nm full width at half maximum (FWHM)) are presented as a function of collision energy in the range Esubc.m. = 5-20 eV. The spectra clearly show an increase in rotational broadening with collision energy. To reasonably fit the spectral data, simulations ... |
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| State-Resolved Reaction Dynamics |
27 JUL 92 |
23 pages |
| Authors:
Richard N. Zare; STANFORD UNIV CA DEPT OF CHEMISTRY
|
| This research effort is comprised of two groups of experiments. The first group measures and characterizes the electron ejected in a photoionization event. The second group is concerned with understanding the role of energy in affecting the outcome of ion-molecule reactions. High resolution, angle-resolved photoelectron spectroscopy was carried out following resonance enhanced multiphoton ionization (REMPI) of nitric oxide. These measurements have led to a complete description of this photoionization event. ... |
|
| Novel Gas Phase Ion Molecule Reactions of C60++ with O2 and NH3 |
29 MAY 92 |
14 pages |
| Authors:
James Stry; M. T. Coolbaugh; Edward Turos; James F. Garvey; STATE UNIV OF NEW YORK AT BUFFALO DEPT OF CHEMISTRY
|
| We have recently utilized a tandem triple quadrupole mass spectrometer to probe the gas phase ion-molecule chemistry of C60++ with a variety of target gases, at low collision energies. We have observed a high degree of reactivity of C60++ with oxygen to produce C60+, C60O2+ and C60O+. Likewise, we have also observed reactivity of C60++ with ammonia to produce C60NH2+, C60NH2(NH3)+, C60NH2(NH3)2+ and C60NH2(NH3)3 . We propose that the product ... |
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| Modeling Study to Evaluate the Ionic Mechanism of Soot Formation |
APR 92 |
37 pages |
| Authors:
H. F. Calcote; R. J. Gill; C. H. Berman; AEROCHEM RESEARCH LABS INC PRINCETON NJ
|
| It has been demonstrated that in a sooting laboratory flame the time to add a carbon atom to a growing carbon species is about the same, or shorter, for the ionic than for the free radical mechanism. The calculated step time is consistent with the experimentally observed time in the flame to build a soot particle. It has also been demonstrated that, up to about 30 carbon atoms, the thermodynamic ... |
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Reports by Keyword(s)
*ION MOLECULE INTERACTIONS
