1
|
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
| |
Collapse
|
2
|
Link MF, Farmer DK, Berg T, Flocke F, Ravishankara AR. Measuring Photodissociation Product Quantum Yields Using Chemical Ionization Mass Spectrometry: A Case Study with Ketones. J Phys Chem A 2021; 125:6836-6844. [PMID: 34324344 DOI: 10.1021/acs.jpca.1c03140] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Measurements of photolysis quantum yields are challenging because of the difficulties in measuring the first-generation photodissociation products, interference from other products or contaminants, sufficient photon fluxes and/or low absorption cross sections of the photolyte to make detectable amounts of products, and quantification of the photon flux. In the case of acetone (and other atmospherically relevant ketones) the uncertainty in the photolysis quantum yield creates uncertainty in the calculated OH radical and acyl peroxy nitrate production in the atmosphere. We present a new method for determining photodissociation product quantum yields by measuring acyl peroxy radicals (RC(O)O2) produced in the photolysis of ketones in air using chemical ionization mass spectrometry (CIMS). We show good agreement of our CIMS method with previously published quantum yields of the acyl radical from photolysis of biacetyl and methyl ethyl ketone (MEK) at 254 nm. Additionally, we highlight the capabilities of this CIMS method through the measurement of photolysis branching ratios for MEK. We suggest future applications of CIMS (in the laboratory and field) to measure RC(O)O2 and associated photolysis processes.
Collapse
Affiliation(s)
- Michael F Link
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Delphine K Farmer
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Tyson Berg
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Frank Flocke
- National Center for Atmospheric Research, Boulder, Colorado 80301, United States
| | - A R Ravishankara
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States.,Department of Atmospheric Science, Colorado State University, Fort Collins, Colorado 80523, United States
| |
Collapse
|
3
|
Hüter O, Temps F. Ultrafast α -CC bond cleavage of acetone upon excitation to 3p and 3d Rydberg states by femtosecond time-resolved photoelectron imaging. J Chem Phys 2018; 145:214312. [PMID: 28799347 DOI: 10.1063/1.4971243] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The radiationless electronic relaxation and α -CC bond fission dynamics of jet-cooled acetone in the S1 (nπ*) state and in high-lying 3p and 3d Rydberg states have been investigated by femtosecond time-resolved mass spectrometry and photoelectron imaging. The S1 state was accessed by absorption of a UV pump photon at selected wavelengths between λ = 320 and 250 nm. The observed acetone mass signals and the S1 photoelectron band decayed on sub-picosecond time scales, consistent with a recently proposed ultrafast structural relaxation of the molecules in the S1 state away from the Franck-Condon probe window. No direct signatures could be observed by the experiments for CC dissociation on the S1 potential energy hypersurface in up to 1 ns. The observed acetyl mass signals at all pump wavelengths turned out to be associated with absorption by the molecules of one or more additional pump and/or probe photons. In particular, absorption of a second UV pump photon by the S1 (nπ*) state was found to populate a series of high-lying states belonging to the n = 3 Rydberg manifold. The respective transitions are favored by much larger cross sections compared to the S1 ← S0 transition. The characteristic energies revealed by the photoelectron images allowed for assignments to the 3p and 3dyz states. At two-photon excitation energies higher than 8.1 eV, an ultrafast reaction pathway for breaking the α -CC bond in 50-90 fs via the 3dyz Rydberg state and the elusive ππ* state was observed, explaining the formation of acetyl radicals after femtosecond laser excitation of acetone at these wavelengths.
Collapse
Affiliation(s)
- O Hüter
- Institute of Physical Chemistry, Christian-Albrechts-University Kiel, Olshausenstr. 40, D-24098 Kiel, Germany
| | - F Temps
- Institute of Physical Chemistry, Christian-Albrechts-University Kiel, Olshausenstr. 40, D-24098 Kiel, Germany
| |
Collapse
|
4
|
Groß CBM, Dillon TJ, Crowley JN. Pressure dependent OH yields in the reactions of CH3CO and HOCH2CO with O2. Phys Chem Chem Phys 2014; 16:10990-8. [DOI: 10.1039/c4cp01108b] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
5
|
Seidel L, Hoyermann K, Mauß F, Nothdurft J, Zeuch T. Pressure dependent product formation in the photochemically initiated allyl + allyl reaction. Molecules 2013; 18:13608-22. [PMID: 24192913 PMCID: PMC6270213 DOI: 10.3390/molecules181113608] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Revised: 10/17/2013] [Accepted: 10/22/2013] [Indexed: 11/16/2022] Open
Abstract
Photochemically driven reactions involving unsaturated radicals produce a thick global layer of organic haze on Titan, Saturn's largest moon. The allyl radical self-reaction is an example for this type of chemistry and was examined at room temperature from an experimental and kinetic modelling perspective. The experiments were performed in a static reactor with a volume of 5 L under wall free conditions. The allyl radicals were produced from laser flash photolysis of three different precursors allyl bromide (C3H5Br), allyl chloride (C3H5Cl), and 1,5-hexadiene (CH2CH(CH2)2CHCH2) at 193 nm. Stable products were identified by their characteristic vibrational modes and quantified using FTIR spectroscopy. In addition to the (re-) combination pathway C3H5+C3H5 → C6H10 we found at low pressures around 1 mbar the highest final product yields for allene and propene for the precursor C3H5Br. A kinetic analysis indicates that the end product formation is influenced by specific reaction kinetics of photochemically activated allyl radicals. Above 10 mbar the (re-) combination pathway becomes dominant. These findings exemplify the specificities of reaction kinetics involving chemically activated species, which for certain conditions cannot be simply deduced from combustion kinetics or atmospheric chemistry on Earth.
Collapse
Affiliation(s)
- Lars Seidel
- Lehrstuhl Thermodynamik/Thermische Verfahrenstechnik, BrandenburgischeTechnische-Universität, Siemens-Halske-Ring 8, Cottbus D-03046, Germany; E-Mails: (L.S.); (F.M.)
| | - Karlheinz Hoyermann
- Institut für Physikalische Chemie, Georg-August-Universität, Tammannstr. 6, Göttingen D-37077, Germany; E-Mails: (K.H.); (J.N.)
| | - Fabian Mauß
- Lehrstuhl Thermodynamik/Thermische Verfahrenstechnik, BrandenburgischeTechnische-Universität, Siemens-Halske-Ring 8, Cottbus D-03046, Germany; E-Mails: (L.S.); (F.M.)
| | - Jörg Nothdurft
- Institut für Physikalische Chemie, Georg-August-Universität, Tammannstr. 6, Göttingen D-37077, Germany; E-Mails: (K.H.); (J.N.)
| | - Thomas Zeuch
- Institut für Physikalische Chemie, Georg-August-Universität, Tammannstr. 6, Göttingen D-37077, Germany; E-Mails: (K.H.); (J.N.)
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +49-551-39-33126; Fax: +49-551-39-33117
| |
Collapse
|
6
|
Favero L, Granucci G, Persico M. Dynamics of acetone photodissociation: a surface hopping study. Phys Chem Chem Phys 2013; 15:20651-61. [DOI: 10.1039/c3cp54016b] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
|
7
|
Exploring Multiple Potential Energy Surfaces: Photochemistry of Small Carbonyl Compounds. ACTA ACUST UNITED AC 2012. [DOI: 10.1155/2012/268124] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In theoretical studies of chemical reactions involving multiple potential energy surfaces (PESs) such as photochemical reactions, seams of intersection among the PESs often complicate the analysis. In this paper, we review our recipe for exploring multiple PESs by using an automated reaction path search method which has previously been applied to single PESs. Although any such methods for single PESs can be employed in the recipe, the global reaction route mapping (GRRM) method was employed in this study. By combining GRRM with the proposed recipe, all critical regions, that is, transition states, conical intersections, intersection seams, and local minima, associated with multiple PESs, can be explored automatically. As illustrative examples, applications to photochemistry of formaldehyde and acetone are described. In these examples as well as in recent applications to other systems, the present approach led to discovery of many unexpected nonadiabatic pathways, by which some complicated experimental data have been explained very clearly.
Collapse
|
8
|
Seakins PW, Blitz MA. Developments in Laboratory Studies of Gas-Phase Reactions for Atmospheric Chemistry with Applications to Isoprene Oxidation and Carbonyl Chemistry. Annu Rev Phys Chem 2011; 62:351-73. [PMID: 21219141 DOI: 10.1146/annurev-physchem-032210-102538] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Laboratory studies of gas-phase chemical processes are a key tool in understanding the chemistry of our atmosphere and hence tackling issues such as climate change and air quality. Laboratory techniques have improved considerably with greater emphasis on product detection, allowing the measurement of site-specific rate coefficients. Radical chemistry lies at the heart of atmospheric chemistry. In this review we consider issues around radical generation and recycling from the oxidation of isoprene and from the chemical reactions and photolysis of carbonyl species. Isoprene is the most globally significant hydrocarbon, but uncertainties exist about its oxidation in unpolluted environments. Recent experiments and calculations that cast light on radical generation are reviewed. Carbonyl compounds are the dominant first-generation products from hydrocarbon oxidation. Chemical oxidation can recycle radicals, or photolysis can be a net radical source. Studies have demonstrated that high-resolution and temperature-dependent studies are important for some significant species.
Collapse
Affiliation(s)
| | - Mark A. Blitz
- School of Chemistry, University of Leeds, Leeds, LS2 9JT United Kingdom;
| |
Collapse
|
9
|
Antiñolo M, Jiménez E, Albaladejo J. UV absorption cross sections between 230 and 350 nm and pressure dependence of the photolysis quantum yield at 308 nm of CF3CH2CHO. Phys Chem Chem Phys 2011; 13:15936-46. [DOI: 10.1039/c1cp21368g] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
10
|
Chen SY, Lee YP. Transient infrared absorption of t-CH3C(O)OO, c-CH3C(O)OO, and alpha-lactone recorded in gaseous reactions of CH3CO and O2. J Chem Phys 2010; 132:114303. [PMID: 20331293 DOI: 10.1063/1.3352315] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A step-scan Fourier-transform infrared spectrometer coupled with a multipass absorption cell was utilized to monitor the transient species produced in gaseous reactions of CH(3)CO and O(2); IR absorption spectra of CH(3)C(O)OO and alpha-lactone were observed. Absorption bands with origins at 1851+/-1, 1372+/-2, 1169+/-6, and 1102+/-3 cm(-1) are attributed to t-CH(3)C(O)OO, and those at 1862+/-3, 1142+/-4, and 1078+/-6 cm(-1) are assigned to c-CH(3)C(O)OO. A weak band near 1960 cm(-1) is assigned to alpha-lactone, cyc-CH(2)C(=O)O, a coproduct of OH. These observed rotational contours agree satisfactorily with simulated bands based on predicted rotational parameters and dipole derivatives, and observed vibrational wavenumbers agree with harmonic vibrational wavenumbers predicted with B3LYP/aug-cc-pVDZ density-functional theory. The observed relative intensities indicate that t-CH(3)C(O)OO is more stable than c-CH(3)C(O)OO by 3+/-2 kJ mol(-1). Based on these observations, the branching ratio for the OH+alpha-lactone channel of the CH(3)CO+O(2) reaction is estimated to be 0.04+/-0.01 under 100 Torr of O(2) at 298 K. A simple kinetic model is employed to account for the decay of CH(3)C(O)OO.
Collapse
Affiliation(s)
- Sun-Yang Chen
- Department of Applied Chemistry, National Chiao Tung University, Hsinchu 30010, Taiwan
| | | |
Collapse
|
11
|
Gierczak T, Rajakumar B, Flad JE, Burkholder JB. Kinetic study of the reaction of the acetyl radical, CH3CO, with O3 using cavity ring-down spectroscopy. Chem Phys Lett 2010. [DOI: 10.1016/j.cplett.2009.11.037] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|