1
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Whaley-Mayda L, Guha A, Tokmakoff A. Resonance conditions, detection quality, and single-molecule sensitivity in fluorescence-encoded infrared vibrational spectroscopy. J Chem Phys 2022; 156:174202. [DOI: 10.1063/5.0088435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Fluorescence-encoded Infrared (FEIR) spectroscopy is a vibrational spectroscopy technique that has recently demonstrated the capability of single-molecule sensitivity in solution without near-field enhancement. This work explores the practical experimental factors that are required for successful FEIR measurements in both the single-molecule and bulk regimes. We investigate the role of resonance conditions by performing measurements on a series of coumarin fluorophores of varying electronic transition frequencies. To analyze variations in signal strength and signal to background between molecules, we introduce an FEIR brightness metric that normalizes out measurement-specific parameters. We find that the effect of the resonance condition on FEIR brightness can be reasonably well described by the electronic absorption spectrum. We discuss strategies for optimizing detection quality and sensitivity in bulk and single-molecule experiments.
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Affiliation(s)
| | - Abhirup Guha
- The University of Chicago, United States of America
| | - Andrei Tokmakoff
- Department of Chemistry, University of Chicago, United States of America
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2
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Roberts FC, Lehman JH. Infrared frequency comb spectroscopy of CH 2I 2: Influence of hot bands and pressure broadening on the ν 1 and ν 6 fundamental transitions. J Chem Phys 2022; 156:114301. [DOI: 10.1063/5.0081836] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Direct frequency comb spectroscopy was utilized to measure the vibrational absorption spectrum of diiodomethane, CH2I2, from 2960 to 3125 cm−1. The data were obtained using a CH2I2 concentration of (6.8 ± 1.3) × 1015 molecule cm−3 and a total pressure of 10–300 mbar with either nitrogen or argon as the bath gas. The rovibrational spectra of two fundamental transitions, ν6 and ν1, were recorded and analyzed. We suggest that a significant contribution to the observed congested spectra is due to the population in excited vibrational states of the low energy ν4 I–C–I bend, resulting in transitions 6104nn and 1104nn, where the integer n is the initial vibrational level v = 1–5. PGOPHER was used to fit the experimental spectrum, allowing for rotational constants and other spectral information to be reported. In addition, it was found that the peak widths for the observed transitions were limited by pressure broadening, resulting in a pressure broadening parameter of (0.143 ± 0.006) cm−1 atm−1 by N2 and (0.116 ± 0.006) cm−1 atm−1 by Ar. Further implications for other dihaloalkane infrared spectra are discussed.
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Affiliation(s)
| | - Julia H. Lehman
- School of Chemistry, University of Leeds, Leeds, United Kingdom
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3
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Abstract
The Menshutkin reaction is a methyl transfer reaction relevant in fields ranging from biochemistry to chemical synthesis. In the present work, the energetics and solvent distributions for NH3+MeCl and Pyr+MeBr reactions were investigated in explicit solvent (water, methanol, acetonitrile, benzene, cyclohexane) by means of reactive molecular dynamics simulations. For polar solvents (water, methanol, and acetonitrile) and benzene, strong to moderate catalytic effects for both reactions were found, whereas apolar and bulky cyclohexane interacts weakly with the solute and does not show pronounced barrier reduction. The calculated barrier heights for the Pyr+MeBr reaction in acetonitrile and cyclohexane are 23.2 and 28.1 kcal/mol compared with experimentally measured barriers of 22.5 and 27.6 kcal/mol, respectively. The solvent distributions change considerably between reactant and TS but comparatively little between TS and product conformations of the solute. As the system approaches the transition state, correlated solvent motions occur which destabilize the solvent-solvent interactions. This is required for the system to surmount the barrier. Finally, it is found that the average solvent-solvent interaction energies in the reactant, TS, and product state geometries are correlated with changes in the solvent structure around the solute.
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Affiliation(s)
- Haydar Taylan Turan
- Department of Chemistry, University of Basel, Klingelbergstrasse 80, 4056 Basel, Switzerland
| | - Sebastian Brickel
- Department of Chemistry, University of Basel, Klingelbergstrasse 80, 4056 Basel, Switzerland
| | - Markus Meuwly
- Department of Chemistry, University of Basel, Klingelbergstrasse 80, 4056 Basel, Switzerland
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4
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Park S, Shin J, Yoon H, Pak Y, Lim M. Complete photodissociation dynamics of CF2I2in solution. Phys Chem Chem Phys 2019; 21:6859-6867. [DOI: 10.1039/c9cp00507b] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Photoexcited CF2I2in c-C6H12undergoes various secondary reactions including complex and isomer formation, after ultrafast two- or three-body dissociations.
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Affiliation(s)
- Seongchul Park
- Department of Chemistry and Chemistry Institute for Functional Materials
- Pusan National University
- Busan 46241
- Korea
| | - Juhyang Shin
- Department of Chemistry and Chemistry Institute for Functional Materials
- Pusan National University
- Busan 46241
- Korea
| | - Hojeong Yoon
- Department of Chemistry and Chemistry Institute for Functional Materials
- Pusan National University
- Busan 46241
- Korea
| | - Youngshang Pak
- Department of Chemistry and Chemistry Institute for Functional Materials
- Pusan National University
- Busan 46241
- Korea
| | - Manho Lim
- Department of Chemistry and Chemistry Institute for Functional Materials
- Pusan National University
- Busan 46241
- Korea
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5
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Kushnarenko A, Miloglyadov E, Quack M, Seyfang G. Intramolecular vibrational energy redistribution in HCCCH2X (X = Cl, Br, I) measured by femtosecond pump–probe experiments in a hollow waveguide. Phys Chem Chem Phys 2018; 20:10949-10959. [DOI: 10.1039/c7cp08561c] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Time resolved femtosecond probing of intramolecular energy flow after excitation of the two different infrared CH-chromophores in these bichromophoric molecules shows strong dependence on the chemical environment of the initial excitation.
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Affiliation(s)
- Alexander Kushnarenko
- ETH Zurich, Lab. für Physikalische Chemie
- HCI E235
- Vladimir-Prelog-Weg 1-5/10
- 8093 Zurich
- Switzerland
| | - Eduard Miloglyadov
- ETH Zurich, Lab. für Physikalische Chemie
- HCI E235
- Vladimir-Prelog-Weg 1-5/10
- 8093 Zurich
- Switzerland
| | - Martin Quack
- ETH Zurich, Lab. für Physikalische Chemie
- HCI E235
- Vladimir-Prelog-Weg 1-5/10
- 8093 Zurich
- Switzerland
| | - Georg Seyfang
- ETH Zurich, Lab. für Physikalische Chemie
- HCI E235
- Vladimir-Prelog-Weg 1-5/10
- 8093 Zurich
- Switzerland
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6
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Mereshchenko AS, Butaeva EV, Borin VA, Eyzips A, Tarnovsky AN. Roaming-mediated ultrafast isomerization of geminal tri-bromides in the gas and liquid phases. Nat Chem 2015; 7:562-8. [DOI: 10.1038/nchem.2278] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Accepted: 05/09/2015] [Indexed: 11/09/2022]
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7
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Zhang Y, Improta R, Kohler B. Mode-specific vibrational relaxation of photoexcited guanosine 5'-monophosphate and its acid form: a femtosecond broadband mid-IR transient absorption and theoretical study. Phys Chem Chem Phys 2014; 16:1487-99. [PMID: 24302276 DOI: 10.1039/c3cp53815j] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
UV-pump/broadband-mid-IR-probe transient absorption (TA) experiments and ab initio quantum mechanical (QM) calculations were used to investigate the photophysics in heavy water of the neutral and acid forms of guanosine 5'-monophosphate (GMP and GMPD(+), respectively). Excited GMP undergoes ultrafast internal conversion (IC) and returns to the electronic ground state in less than one picosecond with a large amount of excess vibrational energy. The spectroscopic signals are dominated by vibrational cooling - a process in which the solute dissipates vibrational energy to the solvent. For neutral GMP, cooling proceeds with a time constant of 3 ps. Following IC, at least some medium-frequency modes such as the carbonyl stretch and an in-plane ring vibration are excited, suggesting that the vibrational energy distribution is non-statistical. This is consistent with predicted structural changes upon passage through the S1/S0 conical intersection. GMPD(+) differs from GMP by a single deuteron at the N7 position, but has a dramatically longer lifetime of 200 ps. Vibrational cooling of the S1 state of GMPD(+) was monitored via several medium-frequency modes that were assigned using QM calculations. These medium-frequency modes are also vibrationally excited in a non-statistical fashion. Excitation of these modes is in line with the change in geometry at the S1 minimum of GMPD(+) predicted by QM calculations. Furthermore, these modes relax at different rates, fully consistent with QM calculations, which predict that excited vibrational states of the carbonyl stretch couple strongly to the D2O solvent and thus deactivate via intermolecular energy transfer (IET). In contrast, the ring stretch couples strongly to other ring modes of the guanine chromophore and appears to decay via intramolecular vibrational energy redistribution (IVR).
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Affiliation(s)
- Yuyuan Zhang
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59715, USA.
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8
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Harris SJ, Murdock D, Zhang Y, Oliver TAA, Grubb MP, Orr-Ewing AJ, Greetham GM, Clark IP, Towrie M, Bradforth SE, Ashfold MNR. Comparing molecular photofragmentation dynamics in the gas and liquid phases. Phys Chem Chem Phys 2013; 15:6567-82. [PMID: 23552482 DOI: 10.1039/c3cp50756d] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This article explores the extent to which insights gleaned from detailed studies of molecular photodissociations in the gas phase (i.e. under isolated molecule conditions) can inform our understanding of the corresponding photofragmentation processes in solution. Systems selected for comparison include a thiophenol (p-methylthiophenol), a thioanisole (p-methylthioanisole) and phenol, in vacuum and in cyclohexane solution. UV excitation in the gas phase results in RX-Y (X = O, S; Y = H, CH3) bond fission in all cases, but over timescales that vary by ~4 orders of magnitude - all of which behaviours can be rationalised on the basis of the relevant bound and dissociative excited state potential energy surfaces (PESs) accessed by UV photoexcitation, and of the conical intersections that facilitate radiationless transfer between these PESs. Time-resolved UV pump-broadband UV/visible probe and/or UV pump-broadband IR probe studies of the corresponding systems in cyclohexane solution reveal additional processes that are unique to the condensed phase. Thus, for example, the data clearly reveal evidence of (i) vibrational relaxation of the photoexcited molecules prior to their dissociation and of the radical fragments formed upon X-Y bond fission, and (ii) geminate recombination of the RX and Y products (leading to reformation of the ground state parent and/or isomeric adducts). Nonetheless, the data also show that, in each case, the characteristics (and the timescale) of the initial bond fission process that occurs under isolated molecule conditions are barely changed by the presence of a weakly interacting solvent like cyclohexane. These condensed phase studies are then extended to an ether analogue of phenol (allyl phenyl ether), wherein UV photo-induced RO-allyl bond fission constitutes the first step of a photo-Claisen rearrangement.
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Affiliation(s)
- Stephanie J Harris
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK
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9
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Dunkelberger AD, Kieda RD, Shin JY, Rossi Paccani R, Fusi S, Olivucci M, Fleming Crim F. Photoisomerization and Relaxation Dynamics of a Structurally Modified Biomimetic Photoswitch. J Phys Chem A 2012; 116:3527-33. [DOI: 10.1021/jp300153a] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Adam D. Dunkelberger
- Department of Chemistry, University of Wisconsin—Madison, Madison, Wisconsin
53706, United States
| | - Ryan D. Kieda
- Department of Chemistry, University of Wisconsin—Madison, Madison, Wisconsin
53706, United States
| | - Jae Yoon Shin
- Department of Chemistry, University of Wisconsin—Madison, Madison, Wisconsin
53706, United States
| | | | - Stefania Fusi
- Department
of Chemistry, Università di Siena, Siena I-53100, Italy
| | - Massimo Olivucci
- Department
of Chemistry, Università di Siena, Siena I-53100, Italy
- Department
of Chemistry, Bowling Green State University, Bowling Green, Ohio
43403, United States
| | - F. Fleming Crim
- Department of Chemistry, University of Wisconsin—Madison, Madison, Wisconsin
53706, United States
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10
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von Benten RS, Liu Y, Abel B. Intramolecular Vibrational Energy Redistribution in Aromatic Molecules of Type C6H5X (X = H, D, F, Cl, CH3, CF3). J Phys Chem A 2010; 114:11522-8. [DOI: 10.1021/jp105417a] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Rebekka S. von Benten
- Institut für Physikalische Chemie der Universität Göttingen, Tammannstrasse 6, D-37077 Göttingen, Germany, and Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Universität Leipzig, Linné-Strasse 2, D-04103 Leipzig, Germany
| | - Yaxing Liu
- Institut für Physikalische Chemie der Universität Göttingen, Tammannstrasse 6, D-37077 Göttingen, Germany, and Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Universität Leipzig, Linné-Strasse 2, D-04103 Leipzig, Germany
| | - Bernd Abel
- Institut für Physikalische Chemie der Universität Göttingen, Tammannstrasse 6, D-37077 Göttingen, Germany, and Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Universität Leipzig, Linné-Strasse 2, D-04103 Leipzig, Germany
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11
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von Benten RS, Liu Y, Abel B. Dynamical consequences of symmetry breaking in benzene and difluorobenzene. J Chem Phys 2010; 133:134306. [DOI: 10.1063/1.3497650] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
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12
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Pein BC, Seong NH, Dlott DD. Vibrational Energy Relaxation of Liquid Aryl-Halides X-C6H5 (X = F, Cl, Br, I). J Phys Chem A 2010; 114:10500-7. [DOI: 10.1021/jp105716w] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Brandt C. Pein
- School of Chemical Sciences, University of Illinois at Urbana−Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801
| | - Nak-Hyun Seong
- School of Chemical Sciences, University of Illinois at Urbana−Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801
| | - Dana D. Dlott
- School of Chemical Sciences, University of Illinois at Urbana−Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801
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13
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Briney KA, Herman L, Boucher DS, Dunkelberger AD, Crim FF. The Influence of Vibrational Excitation on the Photoisomerization of trans-Stilbene in Solution. J Phys Chem A 2010; 114:9788-94. [DOI: 10.1021/jp102752f] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Kristin A. Briney
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin, 53706
| | - Leslie Herman
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin, 53706
| | - David S. Boucher
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin, 53706
| | - Adam D. Dunkelberger
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin, 53706
| | - F. Fleming Crim
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin, 53706
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14
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Sibert EL, Ramesh SG, Gulmen TS. Vibrational Relaxation of OH and CH Fundamentals of Polar and Nonpolar Molecules in the Condensed Phase. J Phys Chem A 2008; 112:11291-305. [DOI: 10.1021/jp8068442] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Edwin L. Sibert
- Department of Chemistry and Theoretical Chemistry Institute, University of Wisconsin—Madison, Madison, Wisconsin 53706
| | - Sai G. Ramesh
- Department of Chemistry and Theoretical Chemistry Institute, University of Wisconsin—Madison, Madison, Wisconsin 53706
| | - Tolga S. Gulmen
- Department of Chemistry and Theoretical Chemistry Institute, University of Wisconsin—Madison, Madison, Wisconsin 53706
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15
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Crim FF. Chemical dynamics of vibrationally excited molecules: Controlling reactions in gases and on surfaces. Proc Natl Acad Sci U S A 2008; 105:12654-61. [PMID: 18765816 PMCID: PMC2529117 DOI: 10.1073/pnas.0803010105] [Citation(s) in RCA: 134] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2008] [Indexed: 11/18/2022] Open
Abstract
Experimental studies of the chemical reaction dynamics of vibrationally excited molecules reveal the ability of different vibrations to control the course of a reaction. This Perspective describes those studies for the prototypical reaction of vibrationally excited methane and its isotopologues in gases and on surfaces and looks to the prospects of similar studies in liquids. The influences of vibrational excitation on the C-H bond cleavage in a single collision reaction with Cl and in dissociative adsorption on a Ni surface bear some striking similarities. Both reactions are bond-selective processes in which the initial preparation of a molecular eigenstate containing a large component of C-H stretching results in preferential cleavage of that bond. It is possible to cleave either the C-H bond or C-D bond in the reaction of Cl with CH3D, CH2D2, or CHD3 and, similarly, to use initial excitation of the C-H stretch to promote dissociation of CHD3 to CD3 and H on a Ni surface. Different vibrational modes, such as the symmetric and antisymmetric stretches in CH3D or CH4, lead to very different reactivities, and molecules with the symmetric stretching vibration excited can be as much as 10 times more reactive than ones with the antisymmetric stretch excited. The origin of this behavior lies in the change in the vibrational motion induced by the interaction with the atomic reaction partner or the surface.
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Affiliation(s)
- F Fleming Crim
- Department of Chemistry, University of Wisconsin, Madison, WI 53706, USA.
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16
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Pearson BJ, Nichols SR, Weinacht T. Molecular fragmentation driven by ultrafast dynamic ionic resonances. J Chem Phys 2007; 127:131101. [DOI: 10.1063/1.2790419] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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17
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Middleton CT, Cohen B, Kohler B. Solvent and Solvent Isotope Effects on the Vibrational Cooling Dynamics of a DNA Base Derivative. J Phys Chem A 2007; 111:10460-7. [PMID: 17910423 DOI: 10.1021/jp0740595] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Vibrational cooling by 9-methyladenine was studied in a series of solvents by femtosecond transient absorption spectroscopy. Signals at UV and near-UV probe wavelengths were assigned to hot ground state population created by ultrafast internal conversion following electronic excitation by a 267 nm pump pulse. A characteristic time for vibrational cooling was determined from bleach recovery signals at 250 nm. This time increases progressively in H2O (2.4 ps), D2O (4.2 ps), methanol (4.5 ps), and acetonitrile (13.1 ps), revealing a pronounced solvent effect on the dissipation of excess vibrational energy. The trend also indicates that the rate of cooling is enhanced in solvents with a dense network of hydrogen bonds. The faster rate of cooling seen in H2O vs D2O is noteworthy in view of the similar hydrogen bonding and macroscopic thermal properties of both liquids. We propose that the solvent isotope effect arises from differences in the rates of solute-solvent vibrational energy transfer. Given the similarities of the vibrational friction spectra of H2O and D2O at low frequencies, the solvent isotope effect may indicate that a considerable portion of the excess energy decays by exciting relatively high frequency (>/=700 cm-1) solvent modes.
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Affiliation(s)
- Chris T Middleton
- Department of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, USA
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18
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Gündoğdu K, Nydegger MW, Bandaria JN, Hill SE, Cheatum CM. Vibrational relaxation of C-D stretching vibrations in CDCl3, CDBr3, and CDI3. J Chem Phys 2007; 125:174503. [PMID: 17100450 DOI: 10.1063/1.2361288] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
We present time-resolved transient grating measurements of the vibrational relaxation rates of the C-D stretching vibrations of deuterated haloforms in benzene and acetone. We compare our results with previous measurements of excited C-H stretches in the same solvents to obtain insight into the solvent effect on the vibrational relaxation. In deuterated molecules, there are more low-order-coupled states and the states are closer in energy to the C-D stretch than in the unlabeled isotopologs. Therefore, the relaxation is faster for the deuterated molecules. The relaxation also shows a significant solvent dependence. Bromoform and iodoform form charge-transfer complexes with both benzene and acetone which enhance the relaxation rate. For chloroform, hydrogen bonding to acetone is expected to be a more favorable interaction. Surprisingly, however, the vibrational relaxation of CDCl(3) is slower in acetone than in benzene.
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Affiliation(s)
- Kenan Gündoğdu
- Chemistry Department, The University of Iowa, Iowa City, IA 52242, USA
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19
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Ramesh SG, Sibert EL. Time scales and pathways of vibrational energy relaxation in liquid CHBr3 and CDBr3. J Chem Phys 2006; 125:244512. [PMID: 17199360 DOI: 10.1063/1.2403875] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Molecular dynamics simulations are used in conjunction with Landau-Teller, fluctuating Landau-Teller, and time-dependent perturbation theories to investigate energy flow out of various vibrational states of liquid CHBr3 and CDBr3. The CH stretch overtone is found to relax with a time scale of about 1 ps compared to the 50 ps rate for the fundamental. The relaxation pathways and rates for the CD stretch decay in CDBr3 are computed in order to understand the changes arising from deuteration. While the computed relaxation rate agrees well with experiments, the pathway is found to be more complex than anticipated. In addition to the above channels for CH(D) stretch relaxation that involve only the hindered translations and rotations of the solvent, routes involving off-resonant and resonant excitations of solvent vibrational modes are also examined. Finally, the decay of energy from low frequency states to near-lying solute states and solvent vibrations are studied.
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Affiliation(s)
- Sai G Ramesh
- Theoretical Chemistry Institute, Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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20
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Abstract
▪ Abstract Modern ultrafast spectroscopic techniques provide new opportunities to study chemical reaction dynamics in liquids and hold the possibility of obtaining much of the same detailed information available in gases. Vibrational energy transfer studies are the most advanced of the investigations and demonstrate that it is possible to observe state-specific pathways of energy flow within a vibrationally excited molecule (intramolecular vibrational relaxation) and into the surrounding solvent molecules (intermolecular energy transfer). Energy transfer in liquids and gases share many common aspects, but the presence of the solvent also alters the relaxation in both obvious and subtle ways. Photodissociation is amenable to similarly detailed study in liquids, and there are informative new measurements. Bimolecular reactions have received the least attention in state-resolved measurements in liquids, but the means to carry them much further now exist. Studying photodissociation and bimolecular reaction of molecules prepared with initial vibrational excitation in liquids is a realistic, but challenging, goal.
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Affiliation(s)
- Christopher G Elles
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA.
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21
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Cox MJ, Crim FF. Vibrational Energy Flow Rates for cis- and trans-Stilbene Isomers in Solution. J Phys Chem A 2005; 109:11673-8. [PMID: 16366616 DOI: 10.1021/jp054263x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Transient electronic absorption following excitation of the first C-H stretching overtone (2nu(CH)) or a C-H stretch-bend combination (nu(CH) + nu(bend)) monitors the flow of vibrational energy in cis-stilbene and in trans-stilbene. Following a rapid initial rise as energy flows into states interrogated by the probe pulse, the absorption decays with two time constants, which are about a factor of 2 longer for the cis-isomer than for the trans-isomer. The decay times for cis-stilbene are tau2(cis) = (2.6 +/- 1.5) ps and tau3(cis) = (24.1 +/- 2.1) ps, and those for trans-stilbene are tau2(trans) = (1.4 +/- 0.6) ps and tau3(trans) = (10.2 +/- 1.1) ps. The decay times are essentially the same in different solvents, suggesting that the relaxation is primarily intramolecular. The two decay times are consistent with the sequential flow of energy through sets of coupled states within the molecule, and the difference in the rates for the two isomers likely reflects differences in coupling among the states arising from the different structures of the isomers. The similarity of the time evolution following excitation of the first C-H overtone at 5990 cm(-1) and the stretch-bend combination at 4650 cm(-1) is consistent with a subset of states, whose structure is similar for the two vibrational excitation energies, controlling the observed flow of energy.
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Affiliation(s)
- M Jocelyn Cox
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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22
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Lenzer T, Oum K, Schroeder J, Sekiguchi K. Gas-Phase Collisional Relaxation of the CH2I Radical after UV Photolysis of CH2I2. J Phys Chem A 2005; 109:10824-31. [PMID: 16331925 DOI: 10.1021/jp053686w] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Transient UV absorption spectra and kinetics of the CH(2)I radical in the gas phase have been investigated at 313 K. Following laser photolysis of 1-3 mbar CH(2)I(2) at 308 nm, transient spectra in the wavelength range 330-390 nm were measured at delay times between 60 ns and a few microseconds. The change of the absorption spectra at early times was attributed to vibrational cooling of highly excited CH(2)I radicals by collisional energy transfer to CH(2)I(2) molecules. From transient absorption decays measured at specific wavelengths, time-dependent concentrations of vibrationally "hot" and "cold" CH(2)I and CH(2)I(2) were extracted by kinetic modeling. In addition, the transient absorption spectrum of CH(2)I radicals between 330 and 400 nm was reconstructed from the simulated concentration-time profiles. The evolution of the absorption spectra of CH(2)I radicals and CH(2)I(2) due to collisional energy transfer was simulated in the framework of a modified Sulzer-Wieland model. Additional master equation simulations for the collisional deactivation of CH(2)I by CH(2)I(2) yield DeltaE values in reasonable agreement with earlier direct studies on the collisional relaxation of other systems. In addition, the simulations show that the shape of the vibrational population distribution of the hot CH(2)I radicals has no influence on the measured UV absorption signals. The implications of our results with respect to spectral assignments in recent ultrafast spectrokinetic studies of the photolysis of CH(2)I(2) in dense fluids are discussed.
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Affiliation(s)
- Thomas Lenzer
- Institut für Physikalische Chemie, Universität Göttingen, Tammannstrasse 6, D-37077 Göttingen, Germany
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Juban EA, McCusker JK. Ultrafast Dynamics of 2E State Formation in Cr(acac)3. J Am Chem Soc 2005; 127:6857-65. [PMID: 15869309 DOI: 10.1021/ja042153i] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Femtosecond time-resolved absorption spectroscopy has been used to elucidate the excited-state dynamics associated with formation of the (2)E excited state in a Cr(III) transition metal complex. Cr(acac)(3) (where acac is the deprotonated monoanion of acetylacetone) exhibits monophasic decay kinetics with tau = 1.1 +/- 0.1 ps following excitation into the lowest-energy ligand-field absorption band; the time constant is found to be independent of both excitation and probe wavelength across the entire (4)A(2) --> (4)T(2) absorption envelope. The lack of a significant shift in the excited-state absorption spectrum combined with the observed spectral narrowing is consistent with an assignment of this process as vibrational cooling (k(vib)) in the (2)E state. The data on Cr(acac)(3) indicate that intersystem crossing associated with the (4)T(2) --> (2)E conversion occurs at a rate k(ISC) > 10(13) s(-)(1) and furthermore competes effectively with vibrational relaxation in the initially formed (4)T(2) state. Excitation into the higher energy (4)LMCT state (lambda(ex) = 336 nm) gives rise to biphasic kinetics with tau( 1) = 50 +/- 20 fs and tau( 2) = 1.2 +/- 0.2 ps. The slower component is again assigned to vibrational cooling in the (2)E state, whereas the subpicosecond process is attributed to conversion from the charge-transfer to the ligand-field manifold. In addition to detailing a process central to the photophysics of Cr(III), these results reinforce the notion that the conventional picture of excited-state dynamics in which k(vib) > k(IC) > k(ISC) does not generally apply when describing excited-state formation in transition metal complexes.
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Affiliation(s)
- Eric A Juban
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA
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24
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Graham PB, Matus KJM, Stratt RM. The workings of a molecular thermometer: The vibrational excitation of carbon tetrachloride by a solvent. J Chem Phys 2004; 121:5348-55. [PMID: 15352828 DOI: 10.1063/1.1784441] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
An intriguing energy-transfer experiment was recently carried out in methanol/carbon tetrachloride solutions. It turned out to be possible to watch vibrational energy accumulating in three of carbon tetrachloride's modes following initial excitation of O-H and C-H stretches in methanol, in effect making those CCl(4) modes "molecular thermometers" reporting on methanol's relaxation. In this paper, we use the example of a CCl(4) molecule dissolved in liquid argon to examine, on a microscopic level, just how this kind of thermal activation occurs in liquid solutions. The fact that even the lowest CCl(4) mode has a relatively high frequency compared to the intermolecular vibrational band of the solvent means that the only solute-solvent dynamics relevant to the vibrational energy transfer will be extraordinarily local, so much so that it is only the force between the instantaneously most prominent Cl and solvent atoms that will significantly contribute to the vibrational friction. We use this observation, within the context of a classical instantaneous-pair Landau-Teller calculation, to show that energy flows into CCl(4) primarily via one component of the nominally degenerate, lowest frequency, E mode and does so fast enough to make CCl(4) an excellent choice for monitoring methanol relaxation. Remarkably, within this theory, the different symmetries and appearances of the different CCl(4) modes have little bearing on how well they take up energy from their surroundings--it is only how high their vibrational frequencies are relative to the solvent intermolecular vibrational band edge that substantially favors one mode over another.
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Affiliation(s)
- Polly B Graham
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA
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25
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Elles CG, Cox MJ, Crim FF. Vibrational relaxation of CH3I in the gas phase and in solution. J Chem Phys 2004; 120:6973-9. [PMID: 15267596 DOI: 10.1063/1.1676292] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Transient electronic absorption measurements reveal the vibrational relaxation dynamics of CH(3)I following excitation of the C-H stretch overtone in the gas phase and in liquid solutions. The isolated molecule relaxes through two stages of intramolecular vibrational relaxation (IVR), a fast component that occurs in a few picoseconds and a slow component that takes place in about 400 ps. In contrast, a single 5-7 ps component of IVR precedes intermolecular energy transfer (IET) to the solvent, which dissipates energy from the molecule in 50 ps, 44 ps, and 16 ps for 1 M solutions of CH(3)I in CCl(4), CDCl(3), and (CD(3))(2)CO, respectively. The vibrational state structure suggests a model for the relaxation dynamics in which a fast component of IVR populates the states that are most strongly coupled to the initially excited C-H stretch overtone, regardless of the environment, and the remaining, weakly coupled states result in a secondary relaxation only in the absence of IET.
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Affiliation(s)
- Christopher G Elles
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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26
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von Benten R, Charvat A, Link O, Abel B, Schwarzer D. Intramolecular vibrational energy redistribution and intermolecular energy transfer of benzene in supercritical CO2: measurements from the gas phase up to liquid densities. Chem Phys Lett 2004. [DOI: 10.1016/j.cplett.2004.01.043] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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27
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Yoo HS, DeWitt MJ, Pate BH. Vibrational Dynamics of Terminal Acetylenes: II. Pathway for Vibrational Relaxation in Gas and Solution. J Phys Chem A 2004. [DOI: 10.1021/jp027546n] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Hyun S. Yoo
- Department of Chemistry, University of Virginia, McCormick Road, Charlottesville, Virginia 22904
| | - Merrick J. DeWitt
- Department of Chemistry, University of Virginia, McCormick Road, Charlottesville, Virginia 22904
| | - Brooks H. Pate
- Department of Chemistry, University of Virginia, McCormick Road, Charlottesville, Virginia 22904
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Yoo HS, DeWitt MJ, Pate BH. Vibrational Dynamics of Terminal Acetylenes: I. Comparison of the Intramolecular Vibrational Energy Redistribution Rate of Gases and the Total Relaxation Rate of Dilute Solutions at Room Temperature. J Phys Chem A 2004. [DOI: 10.1021/jp027543a] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Hyun S. Yoo
- Department of Chemistry, University of Virginia, McCormick Road, Charlottesville, Virginia 22904
| | - Merrick J. DeWitt
- Department of Chemistry, University of Virginia, McCormick Road, Charlottesville, Virginia 22904
| | - Brooks H. Pate
- Department of Chemistry, University of Virginia, McCormick Road, Charlottesville, Virginia 22904
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29
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Yoo HS, McWhorter DA, Pate BH. Vibrational Dynamics of Terminal Acetylenes: III. Comparison of the Acetylenic C−H Stretch Intramolecular Vibrational-Energy Redistribution Rates in Ultracold Molecular Beams, Room-Temperature Gases, and Room-Temperature Dilute Solutions. J Phys Chem A 2004. [DOI: 10.1021/jp0275443] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Hyun S. Yoo
- Department of Chemistry, University of Virginia, McCormick Road, Charlottesville, Virginia 22904
| | - David A. McWhorter
- Department of Chemistry, University of Virginia, McCormick Road, Charlottesville, Virginia 22904
| | - Brooks H. Pate
- Department of Chemistry, University of Virginia, McCormick Road, Charlottesville, Virginia 22904
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30
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von Benten R, Link O, Abel B, Schwarzer D. The Impact of a Solvent and a Methyl Rotor on Timescales of Intramolecular Vibrational Energy Redistribution in Aromatic Molecules. J Phys Chem A 2003. [DOI: 10.1021/jp030974o] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- R. von Benten
- Institut für Physikalische Chemie der Universität Göttingen, Tammannstrasse 6, D-37077 Göttingen, Germany
| | - O. Link
- Institut für Physikalische Chemie der Universität Göttingen, Tammannstrasse 6, D-37077 Göttingen, Germany
| | - B. Abel
- Institut für Physikalische Chemie der Universität Göttingen, Tammannstrasse 6, D-37077 Göttingen, Germany
| | - D. Schwarzer
- MPI für biophysikalische Chemie, Am Fassberg 11, D-37077 Göttingen, Germany
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31
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Assmann J, von Benten R, Charvat A, Abel B. Intra- and Intermolecular Vibrational Energy Relaxation of C−H Overtone Excited Benzonitrile, para-Difluorobenzene, and Pyrazine in Solution. J Phys Chem A 2003. [DOI: 10.1021/jp027368y] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- J. Assmann
- Institut für Physikalische Chemie der Universität Göttingen, Tammannstrasse 6, D-37077 Göttingen, Germany
| | - R. von Benten
- Institut für Physikalische Chemie der Universität Göttingen, Tammannstrasse 6, D-37077 Göttingen, Germany
| | - A. Charvat
- Institut für Physikalische Chemie der Universität Göttingen, Tammannstrasse 6, D-37077 Göttingen, Germany
| | - B. Abel
- Institut für Physikalische Chemie der Universität Göttingen, Tammannstrasse 6, D-37077 Göttingen, Germany
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32
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Abel B, Assmann J, Botschwina P, Buback M, Kling M, Oswald R, Schmatz S, Schroeder J, Witte T. Experimental and Theoretical Investigations of the Ultrafast Photoinduced Decomposition of Organic Peroxides in Solution: Formation and Decarboxylation of Benzoyloxy Radicals. J Phys Chem A 2003. [DOI: 10.1021/jp034858x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Bernd Abel
- Institut für Physikalische Chemie, Universität Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany
| | - Jens Assmann
- Institut für Physikalische Chemie, Universität Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany
| | - Peter Botschwina
- Institut für Physikalische Chemie, Universität Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany
| | - Michael Buback
- Institut für Physikalische Chemie, Universität Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany
| | - Matthias Kling
- Institut für Physikalische Chemie, Universität Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany
| | - Rainer Oswald
- Institut für Physikalische Chemie, Universität Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany
| | - Stefan Schmatz
- Institut für Physikalische Chemie, Universität Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany
| | - Jörg Schroeder
- Institut für Physikalische Chemie, Universität Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany
| | - Thomas Witte
- Institut für Physikalische Chemie, Universität Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany
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33
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Elles CG, Bingemann D, Heckscher MM, Crim FF. Vibrational relaxation of CH2I2 in solution: Excitation level dependence. J Chem Phys 2003. [DOI: 10.1063/1.1554396] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
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34
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Kwok WM, Ma C, Parker AW, Phillips D, Towrie M, Matousek P, Phillips DL. Picosecond Time-Resolved Resonance Raman Study of CH2I−I Produced after Ultraviolet Photolysis of CH2I2 in CH3OH, CH3CN/H2O and CH3OH/H2O Solutions. J Phys Chem A 2003. [DOI: 10.1021/jp021611b] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Wai Ming Kwok
- Department of Chemistry, Imperial College of Science, Technology and Medicine, Exhibition Road, London SW7 2AY, U.K., Central Laser Facility, CLRC Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, U.K., and Department of Chemistry, University of Hong Kong, Pokfulam Road, Hong Kong S. A. R., P. R. China
| | - Chensheng Ma
- Department of Chemistry, Imperial College of Science, Technology and Medicine, Exhibition Road, London SW7 2AY, U.K., Central Laser Facility, CLRC Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, U.K., and Department of Chemistry, University of Hong Kong, Pokfulam Road, Hong Kong S. A. R., P. R. China
| | - Anthony W. Parker
- Department of Chemistry, Imperial College of Science, Technology and Medicine, Exhibition Road, London SW7 2AY, U.K., Central Laser Facility, CLRC Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, U.K., and Department of Chemistry, University of Hong Kong, Pokfulam Road, Hong Kong S. A. R., P. R. China
| | - David Phillips
- Department of Chemistry, Imperial College of Science, Technology and Medicine, Exhibition Road, London SW7 2AY, U.K., Central Laser Facility, CLRC Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, U.K., and Department of Chemistry, University of Hong Kong, Pokfulam Road, Hong Kong S. A. R., P. R. China
| | - Michael Towrie
- Department of Chemistry, Imperial College of Science, Technology and Medicine, Exhibition Road, London SW7 2AY, U.K., Central Laser Facility, CLRC Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, U.K., and Department of Chemistry, University of Hong Kong, Pokfulam Road, Hong Kong S. A. R., P. R. China
| | - Pavel Matousek
- Department of Chemistry, Imperial College of Science, Technology and Medicine, Exhibition Road, London SW7 2AY, U.K., Central Laser Facility, CLRC Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, U.K., and Department of Chemistry, University of Hong Kong, Pokfulam Road, Hong Kong S. A. R., P. R. China
| | - David Lee Phillips
- Department of Chemistry, Imperial College of Science, Technology and Medicine, Exhibition Road, London SW7 2AY, U.K., Central Laser Facility, CLRC Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, U.K., and Department of Chemistry, University of Hong Kong, Pokfulam Road, Hong Kong S. A. R., P. R. China
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Assmann J, Benten RV, Charvat A, Abel B. Vibrational Energy Relaxation of Selectively Excited Aromatic Molecules in Solution: The Effect of a Methyl Rotor and Its Chemical Substitution. J Phys Chem A 2003. [DOI: 10.1021/jp026817r] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- J. Assmann
- Institut für Physikalische Chemie der Universität Göttingen, Tammannstrasse 6, D-37077 Göttingen, Germany
| | - R. v. Benten
- Institut für Physikalische Chemie der Universität Göttingen, Tammannstrasse 6, D-37077 Göttingen, Germany
| | - A. Charvat
- Institut für Physikalische Chemie der Universität Göttingen, Tammannstrasse 6, D-37077 Göttingen, Germany
| | - B. Abel
- Institut für Physikalische Chemie der Universität Göttingen, Tammannstrasse 6, D-37077 Göttingen, Germany
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37
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Heckscher MM, Sheps L, Bingemann D, Crim FF. Relaxation of the C–H stretching fundamental vibrations of CHI3, CH2I2, and CH3I in solution. J Chem Phys 2002. [DOI: 10.1063/1.1510668] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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38
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Schwarzer D, Hanisch C, Kutne P, Troe J. Vibrational Energy Transfer in Highly Excited Bridged Azulene-Aryl Compounds: Direct Observation of Energy Flow through Aliphatic Chains and into the Solvent. J Phys Chem A 2002. [DOI: 10.1021/jp0210576] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- D. Schwarzer
- Max-Planck-Institut für Biophysikalische Chemie, Am Fassberg, 37077 Göttingen, Germany
| | - C. Hanisch
- Max-Planck-Institut für Biophysikalische Chemie, Am Fassberg, 37077 Göttingen, Germany
| | - P. Kutne
- Max-Planck-Institut für Biophysikalische Chemie, Am Fassberg, 37077 Göttingen, Germany
| | - J. Troe
- Max-Planck-Institut für Biophysikalische Chemie, Am Fassberg, 37077 Göttingen, Germany
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39
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Tarnovsky AN, Wall M, Gustafsson M, Lascoux N, Sundström V, Åkesson E. Ultrafast Study of the Photodissociation of Bromoiodomethane in Acetonitrile upon 266 nm Excitation. J Phys Chem A 2002. [DOI: 10.1021/jp014306j] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | - Magnus Wall
- Department of Chemical Physics, Lund University, Box 124, SE-221 00 Lund, Sweden
| | - Magnus Gustafsson
- Department of Chemical Physics, Lund University, Box 124, SE-221 00 Lund, Sweden
| | - Noelle Lascoux
- Department of Chemical Physics, Lund University, Box 124, SE-221 00 Lund, Sweden
| | - Villy Sundström
- Department of Chemical Physics, Lund University, Box 124, SE-221 00 Lund, Sweden
| | - Eva Åkesson
- Department of Chemical Physics, Lund University, Box 124, SE-221 00 Lund, Sweden
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40
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Assmann J, Charvat A, Schwarzer D, Kappel C, Luther K, Abel B. Real-Time Observation of Intra- and Intermolecular Vibrational Energy Flow of Selectively Excited Alkyl Iodides in Solution: The Effect of Chemical Substitution. J Phys Chem A 2002. [DOI: 10.1021/jp015552y] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- J. Assmann
- Institut für Physikalische Chemie der Universität Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany, and Max-Planck Institut für Biophysikalsiche Chemie, Am Fassberg, 37077 Göttingen, Germany
| | - A. Charvat
- Institut für Physikalische Chemie der Universität Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany, and Max-Planck Institut für Biophysikalsiche Chemie, Am Fassberg, 37077 Göttingen, Germany
| | - D. Schwarzer
- Institut für Physikalische Chemie der Universität Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany, and Max-Planck Institut für Biophysikalsiche Chemie, Am Fassberg, 37077 Göttingen, Germany
| | - C. Kappel
- Institut für Physikalische Chemie der Universität Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany, and Max-Planck Institut für Biophysikalsiche Chemie, Am Fassberg, 37077 Göttingen, Germany
| | - K. Luther
- Institut für Physikalische Chemie der Universität Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany, and Max-Planck Institut für Biophysikalsiche Chemie, Am Fassberg, 37077 Göttingen, Germany
| | - B. Abel
- Institut für Physikalische Chemie der Universität Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany, and Max-Planck Institut für Biophysikalsiche Chemie, Am Fassberg, 37077 Göttingen, Germany
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41
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Sekiguchi K, Shimojima A, Kajimoto O. Intramolecular and intermolecular vibrational energy relaxation of CH2I2 dissolved in supercritical fluid. Chem Phys Lett 2002. [DOI: 10.1016/s0009-2614(02)00371-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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42
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43
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Sibert EL, Rey R. Vibrational relaxation in liquid chloroform following ultrafast excitation of the CH stretch fundamental. J Chem Phys 2002. [DOI: 10.1063/1.1420488] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
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44
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Cheatum CM, Heckscher MM, Fleming Crim F. Excited-state dynamics in 8-hydroxyquinoline dimers. Chem Phys Lett 2001. [DOI: 10.1016/s0009-2614(01)01173-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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45
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Li YL, Leung KH, Phillips DL. Time-Resolved Resonance Raman Study of the Reaction of Isodiiodomethane with Cyclohexene: Implications for the Mechanism of Photocyclopropanation of Olefins Using Ultraviolet Photolysis of Diiodomethane. J Phys Chem A 2001. [DOI: 10.1021/jp0128527] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yun-Liang Li
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong S. A. R., P. R. China
| | - King Hung Leung
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong S. A. R., P. R. China
| | - David Lee Phillips
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong S. A. R., P. R. China
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46
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Cheatum CM, Heckscher MM, Bingemann D, Crim FF. CH2I2 fundamental vibrational relaxation in solution studied by transient electronic absorption spectroscopy. J Chem Phys 2001. [DOI: 10.1063/1.1404393] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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47
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Phillips DL, Fang WH, Zheng X. Isodiiodomethane is the methylene transfer agent in cyclopropanation reactions with olefins using ultraviolet photolysis of diiodomethane in solutions: a density functional theory investigation of the reactions of isodiiodomethane, iodomethyl radical, and iodomethyl cation with ethylene. J Am Chem Soc 2001; 123:4197-203. [PMID: 11457184 DOI: 10.1021/ja003090g] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We examine the chemical reactions of the isodiiodomethane (CH2I-I), .CH2I and CH2I(+) species with ethylene using density functional theory computations. The CH2I-I species readily reacts with ethylene to give the cyclopropane product and an I2 product via a one-step reaction with a barrier height of approximately 2.9 kcal/mol. However, the.CH2I and CH2I(+) species have much more difficult pathways (with larger potential barriers) to react with ethylene via a two-step reaction mechanism. Comparison of experimental results to our present calculation results indicates that the CH2I-I photoproduct species is most likely the methylene transfer agent for the cyclopropanation reaction of olefins via ultraviolet photoexcitation of diiodomethane.
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Affiliation(s)
- D L Phillips
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong S. A. R., P. R. China
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Charvat A, Aβmann J, Abel B, Schwarzer D. Real-Time Probing of Intramolecular Vibrational Energy Redistribution and Intermolecular Vibrational Energy Transfer of Selectively Excited CH2I2 Molecules in Solution. J Phys Chem A 2001. [DOI: 10.1021/jp004293u] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Ales Charvat
- Institut für Physikalische Chemie, Universität Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany
| | - Jens Aβmann
- Institut für Physikalische Chemie, Universität Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany
| | - Bernd Abel
- Institut für Physikalische Chemie, Universität Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany
| | - Dirk Schwarzer
- Max-Planck Institut für biophysikalische Chemie, Am Fassberg 10, 37077 Göttingen, Germany
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