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Pangerl J, Sukul P, Rück T, Fuchs P, Weigl S, Miekisch W, Bierl R, Matysik FM. An inexpensive UV-LED photoacoustic based real-time sensor-system detecting exhaled trace-acetone. PHOTOACOUSTICS 2024; 38:100604. [PMID: 38559568 PMCID: PMC10973644 DOI: 10.1016/j.pacs.2024.100604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 03/08/2024] [Accepted: 03/20/2024] [Indexed: 04/04/2024]
Abstract
In this research we present a low-cost system for breath acetone analysis based on UV-LED photoacoustic spectroscopy. We considered the end-tidal phase of exhalation, which represents the systemic concentrations of volatile organic compounds (VOCs) - providing clinically relevant information about the human health. This is achieved via the development of a CO2-triggered breath sampling system, which collected alveolar breath over several minutes in sterile and inert containers. A real-time mass spectrometer is coupled to serve as a reference device for calibration measurements and subsequent breath analysis. The new sensor system provided a 3σ detection limit of 8.3 ppbV and an NNEA of 1.4E-9 Wcm-1Hz-0.5. In terms of the performed breath analysis measurements, 12 out of 13 fell within the error margin of the photoacoustic measurement system, demonstrating the reliability of the measurements in the field.
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Affiliation(s)
- Jonas Pangerl
- Sensorik-ApplikationsZentrum (SappZ), Regensburg University of Applied Sciences, Regensburg 93053, Germany
- Institute of Analytical Chemistry, Chemo- and Biosensing, University of Regensburg, Regensburg 93053, Germany
| | - Pritam Sukul
- Rostock Medical Breath Analytics and Technologies (RoMBAT), Dept. of Anaesthesiology, Intensive Care Medicine and Pain Therapy, University Medicine Rostock, Rostock 18057, Germany
| | - Thomas Rück
- Sensorik-ApplikationsZentrum (SappZ), Regensburg University of Applied Sciences, Regensburg 93053, Germany
| | - Patricia Fuchs
- Rostock Medical Breath Analytics and Technologies (RoMBAT), Dept. of Anaesthesiology, Intensive Care Medicine and Pain Therapy, University Medicine Rostock, Rostock 18057, Germany
| | - Stefan Weigl
- Sensorik-ApplikationsZentrum (SappZ), Regensburg University of Applied Sciences, Regensburg 93053, Germany
| | - Wolfram Miekisch
- Rostock Medical Breath Analytics and Technologies (RoMBAT), Dept. of Anaesthesiology, Intensive Care Medicine and Pain Therapy, University Medicine Rostock, Rostock 18057, Germany
| | - Rudolf Bierl
- Sensorik-ApplikationsZentrum (SappZ), Regensburg University of Applied Sciences, Regensburg 93053, Germany
| | - Frank-Michael Matysik
- Institute of Analytical Chemistry, Chemo- and Biosensing, University of Regensburg, Regensburg 93053, Germany
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2
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Guerra C, Rodríguez-Núñez YA, Ensuncho AE. Role of Triplet States in the Photolysis of Proteogenic Amino Acids. Chemphyschem 2024; 25:e202300655. [PMID: 38057134 DOI: 10.1002/cphc.202300655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 11/19/2023] [Indexed: 12/08/2023]
Abstract
This investigation delves into the UV photodissociation of pivotal amino acids (Alanine, Glycine, Leucine, Proline, and Serine) at 213 nm, providing insights into triplet-state deactivation pathways. Utilizing a comprehensive approach involving time-dependent density functional calculations (TD-DFT), multi-configurational methods, and ab-initio molecular dynamics (AIMD) simulations, we scrutinize the excited electronic states (T1 , T2 , and S1 ) subsequent to 213 nm excitation. Our findings demonstrate that α-carbonyl C-C bond-breaking in triplet states exhibits markedly lower barriers than in singlet states (below 5.0 kcal mol-1 ). AIMD simulations corroborate the potential involvement of triplet states in amino acid fragmentation, underscoring the significance of accounting for these states in photochemistry. Chemical bonding analyses unveil distinctive patterns for S1 and T1 states, with the asymmetric redistribution of electron density characterizing the C-C breaking in triplet states, in contrast to the symmetric breaking observed in singlet states. This research complements recent experimental discoveries, enhancing our comprehension of amino acid reactions in the interstellar medium.
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Affiliation(s)
- Cristian Guerra
- Universidad Andrés Bello, Centro de Química Teórica y Computacional (CQTC), Facultad de Ciencias Exactas, Avenida República 275, 8370146, Santiago de Chile, Chile
- Universidad Autónoma de Chile, Facultad de Ingeniería, Avenida Pedro de Valdivia 425, 7500912, Santiago de Chile, Chile
- Universidad de Córdoba, Grupo de Química Computacional, Facultad de Ciencias Básicas, Carrera 6 No. 77-305, Montería-Córdoba, Colombia
| | - Yeray A Rodríguez-Núñez
- Universidad Andrés Bello, Centro de Química Teórica y Computacional (CQTC), Facultad de Ciencias Exactas, Avenida República 275, 8370146, Santiago de Chile, Chile
| | - Adolfo E Ensuncho
- Universidad de Córdoba, Grupo de Química Computacional, Facultad de Ciencias Básicas, Carrera 6 No. 77-305, Montería-Córdoba, Colombia
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3
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Rinaman J, Murray C. Acetylacetone Photolysis at 280 nm Studied by Velocity-Map Ion Imaging. J Phys Chem A 2023; 127:6687-6696. [PMID: 37535453 PMCID: PMC10440790 DOI: 10.1021/acs.jpca.3c01653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 07/17/2023] [Indexed: 08/05/2023]
Abstract
The photolysis of acetylacetone (AcAc) has been studied using velocity-map ion imaging with pulsed nanosecond lasers. The enolone tautomer of AcAc (CH3C(O)CH═C(OH)CH3) was excited in the strong UV absorption band by UV pulses at 280 nm, preparing the S2(ππ*) state, and products were probed after a short time delay by single-photon VUV ionization at 118.2 nm. Two-color UV + VUV time-of-flight mass spectra show enhancement of fragments at m/z = 15, 42, 43, 58, and 85 at the lowest UV pulse energies and depletion of the parent ion at m/z = 100. Ion images of the five major fragments are all isotropic, indicating dissociation lifetimes that are long on the timescale of molecular rotation but shorter than the laser pulse duration (<6 ns). The m/z = 15 and 85 fragments have identical momentum distributions with moderate translational energy release, suggesting that they are formed as a neutral product pair and likely via a Norrish type I dissociation of the enolone to form CH3 + C(O)CH═C(OH)CH3 over a barrier on a triplet surface. The m/z = 43 fragment may be tentatively assigned to the alternative Norrish type I pathway that produces CH3CO + CH2C(O)CH3 on S0 following phototautomerization to the diketone, although alternative mechanisms involving dissociative ionization of a larger primary photoproduct cannot be conclusively ruled out. The m/z = 42 and 58 fragments are not momentum-matched and consequently are not formed as a neutral pair via a unimolecular dissociation pathway on S0. They also likely originate from the dissociative ionization of primary photofragments. RRKM calculations suggest that unimolecular dissociation pathways that lead to molecular products on S0 are generally slow, implying an upper-limit lifetime of <46 ns after excitation at 280 nm. Time-dependent measurements suggest that the observed photofragments likely do not arise from dissociative ionization of energized AcAc S0*.
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Affiliation(s)
- Johanna
E. Rinaman
- Department of Chemistry, University
of California, Irvine, Irvine, California 92697, United States
| | - Craig Murray
- Department of Chemistry, University
of California, Irvine, Irvine, California 92697, United States
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Troß J, Carter-Fenk K, Cole-Filipiak NC, Schrader P, Word M, McCaslin LM, Head-Gordon M, Ramasesha K. Excited-State Dynamics during Primary C-I Homolysis in Acetyl Iodide Revealed by Ultrafast Core-Level Spectroscopy. J Phys Chem A 2023; 127:4103-4114. [PMID: 37103479 DOI: 10.1021/acs.jpca.3c01414] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/28/2023]
Abstract
In typical carbonyl-containing molecules, bond dissociation events follow initial excitation to nπC═O* states. However, in acetyl iodide, the iodine atom gives rise to electronic states with mixed nπC═O* and nσC-I* character, leading to complex excited-state dynamics, ultimately resulting in dissociation. Using ultrafast extreme ultraviolet (XUV) transient absorption spectroscopy and quantum chemical calculations, we present an investigation of the primary photodissociation dynamics of acetyl iodide via time-resolved spectroscopy of core-to-valence transitions of the I atom after 266 nm excitation. The probed I 4d-to-valence transitions show features that evolve on sub-100-fs time scales, reporting on excited-state wavepacket evolution during dissociation. These features subsequently evolve to yield spectral signatures corresponding to free iodine atoms in their spin-orbit ground and excited states with a branching ratio of 1.1:1 following dissociation of the C-I bond. Calculations of the valence excitation spectrum via equation-of-motion coupled cluster with single and double substitutions (EOM-CCSD) show that initial excited states are of spin-mixed character. From the initially pumped spin-mixed state, we use a combination of time-dependent density functional theory (TDDFT)-driven nonadiabatic ab initio molecular dynamics and EOM-CCSD calculations of the N4,5 edge to reveal a sharp inflection point in the transient XUV signal that corresponds to rapid C-I homolysis. By examining the molecular orbitals involved in the core-level excitations at and around this inflection point, we are able to piece together a detailed picture of C-I bond photolysis in which d → σ* transitions give way to d → p excitations as the bond dissociates. We also report theoretical predictions of short-lived, weak 4d → 5d transitions in acetyl iodide, validated by weak bleaching in the experimental transient XUV spectra. This joint experimental-theoretical effort has thus unraveled the detailed electronic structure and dynamics of a strongly spin-orbit coupled system.
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Affiliation(s)
- Jan Troß
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94550, United States
| | - Kevin Carter-Fenk
- Kenneth S. Pitzer Center for Theoretical Chemistry, Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Neil C Cole-Filipiak
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94550, United States
| | - Paul Schrader
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94550, United States
| | - Mi'Kayla Word
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94550, United States
| | - Laura M McCaslin
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94550, United States
| | - Martin Head-Gordon
- Kenneth S. Pitzer Center for Theoretical Chemistry, Department of Chemistry, University of California, Berkeley, California 94720, United States
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Krupa Ramasesha
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94550, United States
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5
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Cornwell ZA, Enders JJ, Harrison AW, Murray C. Temperature‐dependent kinetics of the reactions of CH
2
OO with acetone, biacetyl, and acetylacetone. INT J CHEM KINET 2022. [DOI: 10.1002/kin.21625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
| | - Jonas J. Enders
- Department of Chemistry University of California Irvine California USA
| | | | - Craig Murray
- Department of Chemistry University of California Irvine California USA
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6
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Jacob LSD, Lee KLK, Schmidt TW, Nauta K, Kable SH. The dynamics of CO production from the photolysis of acetone across the whole S1 ← S0 absorption spectrum: Roaming and triple fragmentation pathways. J Chem Phys 2022; 156:094303. [DOI: 10.1063/5.0080904] [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
The unimolecular photodissociation dynamics of acetone spanning the entire S1 ← S0 absorption spectrum have been reinvestigated, with a focus on mechanisms that produce CO. At excitation wavelengths of λ > 305.8 nm, all photoproducts are formed on the S0 state after internal conversion. A roaming mechanism forming C2H6 + CO is active in the window λ = 311.2–305.8 nm. From λ = 305.8 to 262 nm, little or no CO is produced with the photochemistry dominated by the Norrish-type I C–C bond cleavage on the lowest excited triplet state, T1. At higher energy ( λ < 262 nm), an increasing fraction of CH3CO radicals from the primary reaction have sufficient internal energy to spontaneously decompose to CH3 + CO. A new model is presented to account for the kinetic energy distribution of the secondary CH3 radical, allowing us to determine the height of the energetic barrier to CH3CO decomposition as 68 ± 4 kJ mol−1, which lies midway between previous measurements. The fraction of CO from triple fragmentation rises smoothly from 260 to 248 nm. We see no evidence of the return of roaming, or any other S0 reaction, in this higher energy region of the first electronic absorption band.
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Affiliation(s)
- L. S. D. Jacob
- School of Chemistry, University of New South Wales, Kensington, New South Wales 2052, Australia
| | - K. L. K. Lee
- School of Chemistry, University of New South Wales, Kensington, New South Wales 2052, Australia
| | - T. W. Schmidt
- School of Chemistry, University of New South Wales, Kensington, New South Wales 2052, Australia
| | - K. Nauta
- School of Chemistry, University of New South Wales, Kensington, New South Wales 2052, Australia
| | - S. H. Kable
- School of Chemistry, University of New South Wales, Kensington, New South Wales 2052, Australia
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7
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Campbell JS, Nauta K, Kable SH, Hansen CS. Photodissociation dynamics of CF 3CHO: C-C bond cleavage. J Chem Phys 2021; 155:204303. [PMID: 34852470 DOI: 10.1063/5.0073974] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The photodissociation dynamics of jet-cooled trifluoroacetaldehyde (CF3CHO) into radical products, CF3 + HCO, was explored using velocity mapped ion imaging over the wavelength range 297.5 nm ≤λ≤ 342.8 nm (33 613-29 172 cm-1) covering the entire section of the absorption spectrum accessible with solar actinic wavelengths at the ground level. After initial excitation to the first excited singlet state, S1, the radical dissociation proceeds largely via the first excited triplet state, T1, at excitation energies above the T1 barrier. By combining velocity-mapped ion imaging with high-level theory, we place this barrier at 368.3 ± 2.4 kJ mol-1 (30 780 ± 200 cm-1). After exciting to S1 at energies below this barrier, the dissociation proceeds exclusively via the ground electronic state, S0. The dissociation threshold is determined to be 335.7 ± 1.8 kJ mol-1 (28 060 ± 150 cm-1). Using laser-induced fluorescence spectroscopy, the origin of the S1 ← S0 transition is assigned at 28 903 cm-1. The S0 dissociation channel is active at the S1 origin, but the yield significantly increases above 29 100 cm-1 due to enhanced intersystem crossing or internal conversion.
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Affiliation(s)
- Jyoti S Campbell
- School of Chemistry, University of New South Wales, Sydney, NSW, Australia
| | - Klaas Nauta
- School of Chemistry, University of New South Wales, Sydney, NSW, Australia
| | - Scott H Kable
- School of Chemistry, University of New South Wales, Sydney, NSW, Australia
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8
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Cornwell ZA, Harrison AW, Murray C. Kinetics of the Reactions of CH 2OO with Acetone, α-Diketones, and β-Diketones. J Phys Chem A 2021; 125:8557-8571. [PMID: 34554761 DOI: 10.1021/acs.jpca.1c05280] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Rate constants for the reactions between the simplest Criegee intermediate, CH2OO, with acetone, the α-diketones biacetyl and acetylpropionyl, and the β-diketones acetylacetone and 3,3-dimethyl-2,4-pentanedione have been measured at 295 K. CH2OO was produced photochemically in a flow reactor by 355 nm laser flash photolysis of diiodomethane in the presence of excess oxygen. Time-dependent concentrations were measured using broadband transient absorption spectroscopy, and the reaction kinetics was characterized under pseudo-first-order conditions. The bimolecular rate constant for the CH2OO + acetone reaction is measured to be (4.1 ± 0.4) × 10-13 cm3 s-1, consistent with previous measurements. The reactions of CH2OO with the β-diketones acetylacetone and 3,3-dimethyl-2,5-pentanedione are found to have broadly similar rate constants of (6.6 ± 0.7) × 10-13 and (3.5 ± 0.8) × 10-13 cm3 s-1, respectively; these values may be cautiously considered as upper limits. In contrast, α-diketones react significantly faster, with rate constants of (1.45 ± 0.18) × 10-11 and (1.29 ± 0.15) × 10-11 cm3 s-1 measured for biacetyl and acetylpropionyl. The potential energy surfaces for these 1,3-dipolar cycloaddition reactions are characterized at the M06-2X/aug-cc-pVTZ and CBS-QB3 levels of theory and provide additional support to the observed experimental trends. The reactivity of carbonyl compounds with CH2OO is also interpreted by application of frontier molecular orbital theory and predicted using Hammett substituent constants. Finally, the results are compared with other kinetic studies of Criegee intermediate reactions with carbonyl compounds and discussed within the context of their atmospheric relevance.
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Affiliation(s)
- Zachary A Cornwell
- Department of Chemistry, University of California, Irvine, Irvine, California 92697, United States
| | - Aaron W Harrison
- Department of Chemistry, Austin College, Sherman, Texas 75090, United States
| | - Craig Murray
- Department of Chemistry, University of California, Irvine, Irvine, California 92697, United States
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9
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Barker JR. New light on acetone: a master equation model for gas phase photophysics and photochemistry. Mol Phys 2021. [DOI: 10.1080/00268976.2021.1958018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- John R. Barker
- Department of Climate and Space Sciences & Engineering, University of Michigan, Ann Arbor, MI, USA
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10
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Rowell KN, Kable SH, Jordan MJT. Structural Effects on the Norrish Type I α-Bond Cleavage of Tropospherically Important Carbonyls. J Phys Chem A 2019; 123:10381-10396. [DOI: 10.1021/acs.jpca.9b05534] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Keiran N. Rowell
- School of Chemistry, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Scott H. Kable
- School of Chemistry, University of New South Wales, Sydney, New South Wales 2052, Australia
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11
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Saheb V, Zokaie M. Multichannel Gas-Phase Unimolecular Decomposition of Acetone: Theoretical Kinetic Studies. J Phys Chem A 2018; 122:5895-5904. [DOI: 10.1021/acs.jpca.8b02423] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Vahid Saheb
- Department of Chemistry, Shahid Bahonar University of Kerman, Kerman 76169-14111, Iran
| | - Meymanat Zokaie
- Department of Chemistry, Shahid Bahonar University of Kerman, Kerman 76169-14111, Iran
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12
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Harrison AW, Kable SH. Photodissociation dynamics of propanal and isobutanal: The Norrish Type I pathway. J Chem Phys 2018; 148:164308. [DOI: 10.1063/1.5019383] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Aaron W. Harrison
- School of Chemistry, University of New South Wales, New South Wales 2052, Australia
| | - Scott H. Kable
- School of Chemistry, University of New South Wales, New South Wales 2052, Australia
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13
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Toulson BW, Fishman DA, Murray C. Photodissociation dynamics of acetone studied by time-resolved ion imaging and photofragment excitation spectroscopy. Phys Chem Chem Phys 2018; 20:2457-2469. [PMID: 29313039 DOI: 10.1039/c7cp07320h] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The photodissociation dynamics of acetone has been investigated using velocity-map ion imaging and photofragment excitation (PHOFEX) spectroscopy across a range of wavelengths spanning the first absorption band (236-308 nm). The radical products of the Norrish Type I dissociation, methyl and acetyl, as well as the molecular product ketene have been detected by single-photon VUV ionization at 118 nm. Ketene appears to be formed with non-negligible yield at all wavelengths, with a maximum value of Φ ≈ 0.3 at 280 nm. The modest translational energy release is inconsistent with dissociation over high barriers on the S0 surface, and ketene formation is tentatively assigned to a roaming pathway involving frustrated dissociation to the radical products. Fast-moving radical products are detected at λ ≤ 305 nm with total translational energy distributions that extend to the energetic limit, consistent with dissociation occurring near-exclusively on the T1 surface following intersystem crossing. At energies below the T1 barrier a statistical component indicative of S0 dissociation is observed, although dissociation via the S1/S0 conical intersection is absent at shorter wavelengths, in contrast to acetaldehyde. The methyl radical yield is enhanced over that of acetyl in PHOFEX spectra at λ ≤ 260 nm due to the onset of secondary dissociation of internally excited acetyl radicals. Time-resolved ion imaging experiments using picosecond duration pulses at 266 nm find an appearance time constant of τ = 1490 ± 140 ps for CH3 radicals formed on T1. The associated rate is representative of S1 → T1 intersystem crossing. At 284 nm, CH3 is formed on T1 with two distinct timescales: a fast <10 ns component is accompanied by a slower component with τ = 42 ± 7 ns. A two-step mechanism involving fast internal conversion, followed by slower intersystem crossing (S1 → S0 → T1) is proposed to explain the slow component.
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Affiliation(s)
- Benjamin W Toulson
- Department of Chemistry, University of California, Irvine, Irvine, CA 92697, USA.
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14
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Ingle RA, Hansen CS, Elsdon E, Bain M, King SJ, Lee JWL, Brouard M, Vallance C, Turchetta R, Ashfold MNR. Ultraviolet photochemistry of 2-bromothiophene explored using universal ionization detection and multi-mass velocity-map imaging with a PImMS2 sensor. J Chem Phys 2017; 147:013914. [DOI: 10.1063/1.4979559] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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