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Lukashov SS, Martynov II, Poretsky SA, Pravilov AM, Sivokhina MM. Experimental and Theoretical Studies of the HeICl Van der Waals Complexes in the Valence and Ion-pair States. Chemphyschem 2023; 24:e202300274. [PMID: 37377117 DOI: 10.1002/cphc.202300274] [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: 04/17/2023] [Revised: 06/20/2023] [Accepted: 06/20/2023] [Indexed: 06/29/2023]
Abstract
The article presents results of experimental and theoretical analysis of the T-shaped and linear HeICl van der Waals complexes in the valence A1 and ion-pair β1 states as well as the HeICl(A1,vA ,nA ←X0+ ,vX =0,nx and β1,vβ ,nβ ←A1,vA ,nA ) optical transitions (ni are quantum numbers of the vdW) modes). The HeICl(β1,vβ ,nβ )→He+ICl(E0+ ,D ' 2 ${{D}^{{ {\prime}}}2}$ , β1) decay are also studied. Luminescence spectra of the HeICl(β1,vβ =0-3,nβ ) complex electronic (ICl(E0+ ,vE ,D ' 2 , v D ' ${{D}^{{ {\prime}}}2,{v}_{{D}^{{ {\prime}}}}}$ ) and vibrational ICl(β1,vβ ) predissociation products are measured, and branching ratios of decay channels are determined. To construct potential energy surfaces for the HeICl(A1, β1) states, we utilized the intermolecular diatomic-in-molecule perturbation theory first order method. Experimental and calculated spectroscopic characteristics of the A1 and β1 states agree well. Comparison of the experimental and calculated pump-probe, action and excitation spectra shows that the calculated spectra describe the experimental spectra adequately.
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Affiliation(s)
- Sergei S Lukashov
- Department of Physics, Saint Petersburg State University, SPbSU, 7/9 Universitetskaya nab., St. Petersburg, 199034, Russia
| | - Ivan I Martynov
- Department of Physics, Saint Petersburg State University, SPbSU, 7/9 Universitetskaya nab., St. Petersburg, 199034, Russia
| | - Sergey A Poretsky
- Department of Physics, Saint Petersburg State University, SPbSU, 7/9 Universitetskaya nab., St. Petersburg, 199034, Russia
| | - Anatoly M Pravilov
- Department of Physics, Saint Petersburg State University, SPbSU, 7/9 Universitetskaya nab., St. Petersburg, 199034, Russia
| | - Mariia M Sivokhina
- Department of Physics, Saint Petersburg State University, SPbSU, 7/9 Universitetskaya nab., St. Petersburg, 199034, Russia
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2
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Parsons BF, Rivera MR, Onder MK. NO (A) Rotational State Distributions from Photodissociation of the N 2-NO Complex. J Phys Chem A 2022; 126:5729-5737. [PMID: 35994689 DOI: 10.1021/acs.jpca.2c04265] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have recorded the resonance-enhanced multiphoton ionization spectrum for NO (A) products from photodissociation of the N2-NO complex. We made measurements at excitation energies ranging from 28 to 758 cm-1 above the threshold to produce NO (A) + N2 (X) products, and the resulting spectra reveal the NO (A) rotational states formed during dissociation, allowing us to determine the rotational state distribution. At the lowest available energies, 28 and 50 cm-1 above threshold, we observed contributions from NO (A) rotational states that exceed the available energy and must originate from excitation due to hotbands of the complex. At all higher energies, we did not observe any energetically disallowed NO (A) rotational states, and for all available energies above 259 cm-1 the observed rotational transitions do not extend to the maximum allowed by energy conservation. Furthermore, the observed distributions were typically biased toward low rotational states, in contrast with expectations from vibrational predissociation. From the rotational state distributions, we determined the average fraction of energy partitioned into NO (A) rotation, fNO rot, ave, to be 0.088 at the highest available energy, and this fraction increased as the available energy decreased. By combining the average NO (A) rotational energy along with the average center-of-mass translational energy from our previous work, we determined the average rotational energy for the undetected N2 (X) photoproduct. The results showed that the N2 fragment has a higher average rotational energy relative to the NO fragment. Finally, we found that the NO (A) rotational state distribution was colder than expected for a statistical dissociation.
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Affiliation(s)
- Bradley F Parsons
- Department of Chemistry and Biochemistry, Creighton University, 2500 California Plaza, Omaha, Nebraska 68178, United States
| | - Marcos R Rivera
- Department of Chemistry and Biochemistry, Creighton University, 2500 California Plaza, Omaha, Nebraska 68178, United States
| | - Michael K Onder
- Department of Chemistry and Biochemistry, Creighton University, 2500 California Plaza, Omaha, Nebraska 68178, United States
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Horio T, Minamikawa K, Nishizato T, Hashimoto H, Matsumoto K, Arakawa M, Terasaki A. Photoelectron imaging of size-selected metal cluster anions in a quasi-continuous mode. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:083302. [PMID: 36050112 DOI: 10.1063/5.0097968] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Accepted: 07/23/2022] [Indexed: 06/15/2023]
Abstract
We present a novel high-repetition-rate photoelectron imaging (PEI) apparatus for exploring electronic structures of metal cluster anions. A continuous beam of mass-selected metal cluster anions, generated by a magnetron-sputtering cluster-ion source coupled with a quadrupole mass filter, is chopped into sub-megahertz ion bunches using a high-voltage pulser. The quasi-continuous anion beam is introduced into a PEI spectrometer, where the anions are photodetached using a 404 nm (3.07 eV) continuous-wave laser diode. As a demonstration, we acquire photoelectron images for size-selected Ag cluster anions, AgN - (N = 3, 7, 14), and show that each image can be obtained in a short accumulation time (50 s) with a kinetic energy resolution (ΔE/E) of 4% at E = 1.77 eV. The quasi-continuous PEI technique enables high-count-rate, space-charge-free acquisition of photoelectron spectra and angular distributions not only from size-selected metal cluster anions but also from anions prepared by other continuous ion sources, such as electrospray ionization.
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Affiliation(s)
- Takuya Horio
- Department of Chemistry, Faculty of Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Kento Minamikawa
- Department of Chemistry, Faculty of Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Tasuku Nishizato
- Department of Chemistry, Faculty of Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Haruki Hashimoto
- Department of Chemistry, Faculty of Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Kazuaki Matsumoto
- Department of Chemistry, Faculty of Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Masashi Arakawa
- Department of Chemistry, Faculty of Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Akira Terasaki
- Department of Chemistry, Faculty of Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
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4
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Chien TE, Hohmann L, Harding DJ. Near-ambient pressure velocity map imaging. J Chem Phys 2022; 157:034201. [DOI: 10.1063/5.0098495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
We present a new velocity map imaging instrument for studying molecular beam surface scattering in a near-ambient pressure (NAP-VMI) environment. The instrument offers the possibility to study chemical reaction dynamics and kinetics where higher pressures are either desired or unavoidable, adding a new tool to help close the “pressure gap” between surface science and applied catalysis. NAP-VMI conditions are created by two sets of ion optics that guide ions through an aperture and map their velocities. The aperture separates the high pressure ionization region and maintains the necessary vacuum in the detector region. The performance of the NAP-VMI is demonstrated with results from N2O photodissociation and N2 scattering from a Pd(110) surface, which are compared under vacuum and at near-ambient pressure (1 × 10−3 mbar). NAP-VMI has the potential to be applied to, and useful for, a broader range of experiments, including photoelectron spectroscopy and scattering with liquid microjets.
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Affiliation(s)
- Tzu-En Chien
- Department of Chemical Engineering, KTH Royal Institute of Technology, Stockholm 100 44, Sweden
| | - Lea Hohmann
- Department of Chemical Engineering, KTH Royal Institute of Technology, Stockholm 100 44, Sweden
| | - Dan J. Harding
- Department of Chemical Engineering, KTH Royal Institute of Technology, Stockholm 100 44, Sweden
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5
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Ashfold MNR, Kim SK. Non-Born-Oppenheimer effects in molecular photochemistry: an experimental perspective. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2022; 380:20200376. [PMID: 35341307 DOI: 10.1098/rsta.2020.0376] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 06/28/2021] [Indexed: 06/14/2023]
Abstract
Non-adiabatic couplings between Born-Oppenheimer (BO)-derived potential energy surfaces are now recognized as pivotal in describing the non-radiative decay of electronically excited molecules following photon absorption. This opinion piece illustrates how non-BO effects provide photostability to many biomolecules when exposed to ultraviolet radiation, yet in many other cases are key to facilitating 'reactive' outcomes like isomerization and bond fission. The examples are presented in order of decreasing molecular complexity, spanning studies of organic sunscreen molecules in solution, through two families of heteroatom containing aromatic molecules and culminating with studies of isolated gas phase H2O molecules that afford some of the most detailed insights yet available into the cascade of non-adiabatic couplings that enable the evolution from photoexcited molecule to eventual products. This article is part of the theme issue 'Chemistry without the Born-Oppenheimer approximation'.
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Affiliation(s)
| | - Sang Kyu Kim
- Department of Chemistry, KAIST, Daejeon 34141, Republic of Korea
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6
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Crane SW, Ge L, Cooper GA, Carwithen BP, Bain M, Smith JA, Hansen CS, Ashfold MNR. Nonadiabatic Coupling Effects in the 800 nm Strong-Field Ionization-Induced Coulomb Explosion of Methyl Iodide Revealed by Multimass Velocity Map Imaging and Ab Initio Simulation Studies. J Phys Chem A 2021; 125:9594-9608. [PMID: 34709807 DOI: 10.1021/acs.jpca.1c06346] [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
The Coulomb explosion (CE) of jet-cooled CH3I molecules using ultrashort (40 fs), nonresonant 805 nm strong-field ionization at three peak intensities (260, 650, and 1300 TW cm-2) has been investigated by multimass velocity map imaging, revealing an array of discernible fragment ions, that is, Iq+ (q ≤ 6), CHn+ (n = 0-3), CHn2+ (n = 0, 2), C3+, H+, H2+, and H3+. Complementary ab initio trajectory calculations of the CE of CH3IZ+ cations with Z ≤ 14 identify a range of behaviors. The CE of parent cations with Z = 2 and 3 can be well-described using a diatomic-like representation (as found previously) but the CE dynamics of all higher CH3IZ+ cations require a multidimensional description. The ab initio predicted Iq+ (q ≥ 3) fragment ion velocities are all at the high end of the velocity distributions measured for the corresponding Iq+ products. These mismatches are proposed as providing some of the clearest insights yet into the roles of nonadiabatic effects (and intramolecular charge transfer) in the CE of highly charged molecular cations.
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Affiliation(s)
- Stuart W Crane
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, U.K
| | - Lingfeng Ge
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, U.K
| | - Graham A Cooper
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, U.K
| | - Ben P Carwithen
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, U.K
| | - Matthew Bain
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, U.K
| | - James A Smith
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, U.K
| | - Christopher S Hansen
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, U.K
| | - Michael N R Ashfold
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, U.K
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7
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Sakkoula E, van Oorschot BGM, Parker DH. A compact electrostatic lens for velocity map imaging experiments. Mol Phys 2021. [DOI: 10.1080/00268976.2021.1910357] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- E. Sakkoula
- Institute for Molecules and Materials, Radboud University Nijmegen, Nijmegen, Netherlands
| | - B. G. M. van Oorschot
- Institute for Molecules and Materials, Radboud University Nijmegen, Nijmegen, Netherlands
| | - D. H. Parker
- Institute for Molecules and Materials, Radboud University Nijmegen, Nijmegen, Netherlands
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Hua ZF, Zhao YX, Li YQ, Hu GM, Chen Y, Zhao DF. Ion-neutral photofragment coincidence imaging of photodissociation dynamics of ionic species. CHINESE J CHEM PHYS 2021. [DOI: 10.1063/1674-0068/cjcp2007119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Ze-feng Hua
- CAS Center for Excellence in Quantum Information and Quantum Physics, Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Yun-xiao Zhao
- CAS Center for Excellence in Quantum Information and Quantum Physics, Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - You-qing Li
- CAS Center for Excellence in Quantum Information and Quantum Physics, Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Gao-ming Hu
- CAS Center for Excellence in Quantum Information and Quantum Physics, Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Yang Chen
- CAS Center for Excellence in Quantum Information and Quantum Physics, Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Dong-feng Zhao
- CAS Center for Excellence in Quantum Information and Quantum Physics, Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
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9
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Gentleman AS, Iskra A, Köckert H, Mackenzie SR. Photodissociation dynamics and the dissociation energy of vanadium monoxide, VO, investigated using velocity map imaging. Phys Chem Chem Phys 2019; 21:15560-15567. [PMID: 31265053 DOI: 10.1039/c9cp02120e] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Velocity map imaging has been employed to study multi-photon fragmentation of vanadium monoxide (VO) via the C 4Σ- state. The fragmentation dynamics are interpreted in terms of dissociation at the three-photon level, with the first photon weakly resonant with transitions to vibrational energy levels of the C 4Σ- state. The dissociation channels accessed are shown to depend strongly on the vibrational level via which excitation takes place. Analysis of the evolution of the kinetic energy release spectrum with photon energy leads to a refined value for the dissociation energy of ground state VO of D0(VO) = 53 126 ± 263 cm-1.
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Affiliation(s)
- Alexander S Gentleman
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford, OX1 3QZ, UK.
| | - Andreas Iskra
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford, OX1 3QZ, UK.
| | - Hansjochen Köckert
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford, OX1 3QZ, UK.
| | - Stuart R Mackenzie
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford, OX1 3QZ, UK.
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10
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Kobayashi Y, Chang KF, Zeng T, Neumark DM, Leone SR. Direct mapping of curve-crossing dynamics in IBr by attosecond transient absorption spectroscopy. Science 2019; 365:79-83. [DOI: 10.1126/science.aax0076] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 06/11/2019] [Indexed: 12/29/2022]
Affiliation(s)
- Yuki Kobayashi
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
| | - Kristina F. Chang
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
| | - Tao Zeng
- Department of Chemistry, Carleton University, Ottawa, Ontario K1S5B6, Canada
| | - Daniel M. Neumark
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Stephen R. Leone
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Department of Physics, University of California, Berkeley, CA 94720, USA
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11
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Hua Z, Feng S, Zhou Z, Liang H, Chen Y, Zhao D. A cryogenic cylindrical ion trap velocity map imaging spectrometer. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2019; 90:013101. [PMID: 30709209 DOI: 10.1063/1.5079264] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 12/15/2018] [Indexed: 06/09/2023]
Abstract
A cryogenic cylindrical ion trap velocity map imaging spectrometer has been developed to study photodissociation spectroscopy and dynamics of gaseous molecular ions and ionic complexes. A cylindrical ion trap made of oxygen-free copper is cryogenically cooled down to ∼7 K by using a closed cycle helium refrigerator and is coupled to a velocity map imaging (VMI) spectrometer. The cold trap is used to cool down the internal temperature of mass selected ions and to reduce the velocity spread of ions after extraction from the trap. For CO2 + ions, a rotational temperature of ∼12 K is estimated from the recorded [1 + 1] two-photon dissociation spectrum, and populations in spin-orbit excited X2Πg,1/2 and vibrationally excited states of CO2 + are found to be non-detectable, indicating an efficient internal cooling of the trapped ions. Based on the time-of-flight peak profile and the image of N3 +, the velocity spread of the ions extracted from the trap, both radially and axially, is interpreted as approximately ±25 m/s. An experimental image of fragmented Ar+ from 307 nm photodissociation of Ar2 + shows that, benefitting from the well-confined velocity spread of the cold Ar2 + ions, a VMI resolution of Δv/v ∼ 2.2% has been obtained. The current instrument resolution is mainly limited by the residual radial speed spread of the parent ions after extraction from the trap.
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Affiliation(s)
- Zefeng Hua
- CAS Center for Excellence in Quantum Information and Quantum Physics, Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Shaowen Feng
- CAS Center for Excellence in Quantum Information and Quantum Physics, Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Zhengfang Zhou
- CAS Center for Excellence in Quantum Information and Quantum Physics, Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Hao Liang
- CAS Center for Excellence in Quantum Information and Quantum Physics, Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Yang Chen
- CAS Center for Excellence in Quantum Information and Quantum Physics, Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Dongfeng Zhao
- CAS Center for Excellence in Quantum Information and Quantum Physics, Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
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12
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Suits AG. Invited Review Article: Photofragment imaging. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:111101. [PMID: 30501356 DOI: 10.1063/1.5045325] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 10/25/2018] [Indexed: 06/09/2023]
Abstract
Photodissociation studies in molecular beams that employ position-sensitive particle detection to map product recoil velocities emerged thirty years ago and continue to evolve with new laser and detector technologies. These powerful methods allow application of tunable laser detection of single product quantum states, simultaneous measurement of velocity and angular momentum polarization, measurement of joint product state distributions for the detected and undetected products, coincident detection of multiple product channels, and application to radicals and ions as well as closed-shell molecules. These studies have permitted deep investigation of photochemical dynamics for a broad range of systems, revealed new reaction mechanisms, and addressed problems of practical importance in atmospheric, combustion, and interstellar chemistry. This review presents an historical overview, a detailed technical account of the range of methods employed, and selected experimental highlights illustrating the capabilities of the method.
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Affiliation(s)
- Arthur G Suits
- Department of Chemistry, University of Missouri, Columbia, Missouri 65211, USA
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13
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Tashiro T, Yoshida M, Ohtsuki Y. Application of optimal control simulation to selective photodissociation of IBr by non-resonant dynamic Stark effects. J Chem Phys 2018; 149:064302. [PMID: 30111151 DOI: 10.1063/1.5029518] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We apply nonlinear optimal control simulation to design a non-resonant control pulse that maximizes the probability of specified photodissociation of IBr by utilizing the non-resonant dynamic Stark effect in the presence of a predetermined pump pulse. The optimal pulses are always composed of several subpulses that increase the target probability considerably depending on the wavelength of the pump pulse. Focusing on the cases of high target probabilities, we systematically examine how the subpulses cooperate with each other on the basis of pulse-partitioning analyses. We show that the subpulses largely cooperate with the pump pulse, which can explain their irradiation timings. On the other hand, the cooperation between the subpulses is mainly expressed as the sum of the contribution from each subpulse.
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Affiliation(s)
- Tomohiro Tashiro
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aramaki Aza-Aoba, Aoba-ku, Sendai 980-8578, Japan
| | - Masataka Yoshida
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aramaki Aza-Aoba, Aoba-ku, Sendai 980-8578, Japan
| | - Yukiyoshi Ohtsuki
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aramaki Aza-Aoba, Aoba-ku, Sendai 980-8578, Japan
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14
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Vieuxmaire OPJ, Nahler NH, Jones JR, Dixon RN, Ashfold MNR. Photodissociation of state selected BrCl cations: Branching ratios and angular anisotropies of the Br product forming channels. Mol Phys 2017. [DOI: 10.1080/00268970500052197a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
| | - N. Hendrik Nahler
- a School of Chemistry , University of Bristol , Bristol , BS8 1TS , UK
| | - J. R. Jones
- a School of Chemistry , University of Bristol , Bristol , BS8 1TS , UK
| | - R. N. Dixon
- a School of Chemistry , University of Bristol , Bristol , BS8 1TS , UK
| | - M. N. R. Ashfold
- a School of Chemistry , University of Bristol , Bristol , BS8 1TS , UK
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15
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Chandler DW, Houston PL, Parker DH. Perspective: Advanced particle imaging. J Chem Phys 2017; 147:013601. [PMID: 28688442 PMCID: PMC5648558 DOI: 10.1063/1.4983623] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 04/18/2017] [Indexed: 11/14/2022] Open
Abstract
Since the first ion imaging experiment [D. W. Chandler and P. L. Houston, J. Chem. Phys. 87, 1445-1447 (1987)], demonstrating the capability of collecting an image of the photofragments from a unimolecular dissociation event and analyzing that image to obtain the three-dimensional velocity distribution of the fragments, the efficacy and breadth of application of the ion imaging technique have continued to improve and grow. With the addition of velocity mapping, ion/electron centroiding, and slice imaging techniques, the versatility and velocity resolution have been unmatched. Recent improvements in molecular beam, laser, sensor, and computer technology are allowing even more advanced particle imaging experiments, and eventually we can expect multi-mass imaging with co-variance and full coincidence capability on a single shot basis with repetition rates in the kilohertz range. This progress should further enable "complete" experiments-the holy grail of molecular dynamics-where all quantum numbers of reactants and products of a bimolecular scattering event are fully determined and even under our control.
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Affiliation(s)
- David W Chandler
- Sandia National Laboratories, Combustion Research Facility, Livermore, California 94550, USA
| | - Paul L Houston
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, USA
| | - David H Parker
- Department of Laser and Molecular Physics, Radboud University of Nijmegen, Nijmegen, Netherlands
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16
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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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17
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Klein LB, Morsing TJ, Livingstone RA, Townsend D, Sølling TI. The effects of symmetry and rigidity on non-adiabatic dynamics in tertiary amines: a time-resolved photoelectron velocity-map imaging study of the cage-amine ABCO. Phys Chem Chem Phys 2016; 18:9715-23. [PMID: 27000487 DOI: 10.1039/c5cp07910a] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The non-adiabatic relaxation dynamics of the tertiary cage-amine azabicyclo[2.2.2]octane (ABCO, also known as quinuclidine) have been investigated following 3p Rydberg excitation at 201 nm using femtosecond time-resolved photoelectron imaging (TRPEI). The aim of the study was to investigate the influence of the rigid and symmetric cage structure found in ABCO on the general non-adiabatic relaxation processes commonly seen in other tertiary aliphatic amines (TAAs). Our data is compared with TRPEI results very recently obtained for several structurally less rigid TAA systems [J. O. F. Thompson et al., Chem. Sci., 2016, 7, 1826-1839] and helps to confirm many of the previously reported findings. The experimental results for ABCO in the short-time (<1 ps) regime strongly support earlier conclusions suggesting that planarization about the N-atom is not a prerequisite for efficient 3p-3s internal conversion. Additionally, individual photoelectron peaks within our ABCO data show no temporal shifts in energy. As confirmed by our supporting quantum mechanical calculations, this demonstrates that neither internal conversion within the 3p manifold or significant conformational re-organization are possible in the ABCO system. This result therefore lends strong additional support to the active presence of such dynamical effects in other, less conformationally restricted TAA species, where photoelectron peak shifts are commonly observed. Finally, the extremely long (>1 ns) 3s Rydberg state lifetime seen in ABCO (relative to other TAA systems at similar excitation energies) serves to illustrate the large influence of symmetry and conformational rigidity on intramolecular vibrational redistribution processes previously implicated in mediating this aspect of the overall relaxation dynamics.
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Affiliation(s)
- Liv B Klein
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark.
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18
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Tiwari AK, Henriksen NE. Phase-only laser control in the weak-field limit: Two-pulse control of IBr photofragmentation revisited. J Chem Phys 2016; 144:014306. [DOI: 10.1063/1.4939247] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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19
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Matsuoka T, Yabushita S. Quantum Interference Effects Theoretically Found in the Photodissociation Processes of the Second Absorption Bands of ICl and IBr Molecules. J Phys Chem A 2015; 119:9609-20. [DOI: 10.1021/acs.jpca.5b05146] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Takahide Matsuoka
- Department of Chemistry,
Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan
| | - Satoshi Yabushita
- Department of Chemistry,
Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan
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20
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Marchetti B, Karsili TNV, Kelly O, Kapetanopoulos P, Ashfold MNR. Near ultraviolet photochemistry of 2-bromo- and 2-iodothiophene: Revealing photoinduced ring opening in the gas phase? J Chem Phys 2015; 142:224303. [DOI: 10.1063/1.4921315] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Barbara Marchetti
- School of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, United Kingdom
| | - Tolga N. V. Karsili
- School of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, United Kingdom
| | - Orla Kelly
- Photek Ltd., 26 Castleham Road, St. Leonards-on-Sea, East Sussex TN38 9NS, United Kingdom
| | - Panos Kapetanopoulos
- Photek Ltd., 26 Castleham Road, St. Leonards-on-Sea, East Sussex TN38 9NS, United Kingdom
| | - Michael N. R. Ashfold
- School of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, United Kingdom
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21
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Wenge AM, Karsili TNV, Rodríguez JD, Cotterell MI, Marchetti B, Dixon RN, Ashfold MNR. Tuning photochemistry: substituent effects on πσ* state mediated bond fission in thioanisoles. Phys Chem Chem Phys 2015; 17:16246-56. [DOI: 10.1039/c5cp01660f] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The electronic branching in the thiophenoxyl radicals formed by UV photolysis of thioanisole can be tuned by placing electron withdrawing/donating substituents at the 4-position.
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Affiliation(s)
- Andreas M. Wenge
- School of Chemistry
- University of Bristol
- Cantock's Close
- Bristol BS8 1TS
- UK
| | | | | | | | - Barbara Marchetti
- School of Chemistry
- University of Bristol
- Cantock's Close
- Bristol BS8 1TS
- UK
| | - Richard N. Dixon
- School of Chemistry
- University of Bristol
- Cantock's Close
- Bristol BS8 1TS
- UK
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22
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Tiwari AK, Henriksen NE. Pulse-train control of photofragmentation at constant field energy. J Chem Phys 2014; 141:204301. [PMID: 25429936 DOI: 10.1063/1.4902061] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We consider a phaselocked two-pulse sequence applied to photofragmentation in the weak-field limit. The two pulses are not overlapping in time, i.e., the energy of the pulse-train is constant for all time delays. It is shown that the relative yield of excited Br (*) in the nonadiabatic process: I + Br* ← IBr → I + Br, changes as a function of time delay when the two excited wave packets interfere. The underlying mechanisms are analyzed and the change in the branching ratio as a function of time delay is only a reflection of a changing frequency distribution of the pulse train; the branching ratio does not depend on the detailed pulse shape.
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Affiliation(s)
- Ashwani K Tiwari
- Indian Institute of Science Education and Research Kolkata, Mohanpur 741 252, India
| | - Niels E Henriksen
- Department of Chemistry, Building 207, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
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23
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Suzuki T. Femtosecond Time-Resolved Photoelectron Imaging Study of Photoinduced Molecular Dynamics. J CHIN CHEM SOC-TAIP 2013. [DOI: 10.1002/jccs.200600014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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24
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Sage AG, Oliver TAA, King GA, Murdock D, Harvey JN, Ashfold MNR. UV photolysis of 4-iodo-, 4-bromo-, and 4-chlorophenol: Competition between C–Y (Y = halogen) and O–H bond fission. J Chem Phys 2013; 138:164318. [DOI: 10.1063/1.4802058] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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25
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Ryazanov M, Reisler H. Improved sliced velocity map imaging apparatus optimized for H photofragments. J Chem Phys 2013; 138:144201. [DOI: 10.1063/1.4798929] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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26
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Reid M, Koehler SPK. Validation of velocity map imaging conditions over larger areas. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2013; 84:044101. [PMID: 23635211 DOI: 10.1063/1.4798646] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We have established through simulations and experiments the area over which Velocity Map Imaging (VMI) conditions prevail. We designed a VMI setup in which we can vary the ionization position perpendicular to the center axis of the time-of-flight spectrometer. We show that weak extraction conditions are far superior over standard three-plate setups if the aim is to increase the ionization volume without distorting VMI conditions. This is important for a number of crossed molecular beam experiments that already utilize weak extraction conditions, but to a greater extent for surface studies where fragments are desorbed or scattered off a surface in all directions. Our results on the dissociation of NO2 at 226 nm show that ionization of the fragments can occur up to ±5.5 mm away from the center axis of the time-of-flight spectrometer without affecting resolution or arrival position.
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Affiliation(s)
- Mike Reid
- School of Chemistry, The University of Manchester, Manchester, United Kingdom
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27
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Roberts GM, Hadden DJ, Bergendahl LT, Wenge AM, Harris SJ, Karsili TNV, Ashfold MNR, Paterson MJ, Stavros VG. Exploring quantum phenomena and vibrational control in σ* mediated photochemistry. Chem Sci 2013. [DOI: 10.1039/c2sc21865h] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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28
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Livingstone RA, Thompson JOF, Iljina M, Donaldson RJ, Sussman BJ, Paterson MJ, Townsend D. Time-resolved photoelectron imaging of excited state relaxation dynamics in phenol, catechol, resorcinol, and hydroquinone. J Chem Phys 2012; 137:184304. [DOI: 10.1063/1.4765104] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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29
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Vidma KV, Frederix PWJM, Parker DH, Baklanov AV. Photodissociation of van der Waals clusters of isoprene with oxygen, C5H8-O2, in the wavelength range 213-277 nm. J Chem Phys 2012; 137:054305. [PMID: 22894346 DOI: 10.1063/1.4737856] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The speed and angular distribution of O atoms arising from the photofragmentation of C(5)H(8)-O(2), the isoprene-oxygen van der Waals complex, in the wavelength region of 213-277 nm has been studied with the use of a two-color dissociation-probe method and the velocity map imaging technique. Dramatic enhancement in the O atoms photo-generation cross section in comparison with the photodissociation of individual O(2) molecules has been observed. Velocity map images of these "enhanced" O atoms consisted of five channels, different in their kinetic energy, angular distribution, and wavelength dependence. Three channels are deduced to be due to the one-quantum excitation of the C(5)H(8)-O(2) complex into the perturbed Herzberg III state ((3)Δ(u)) of O(2). This excitation results in the prompt dissociation of the complex giving rise to products C(5)H(8)+O+O when the energy of exciting quantum is higher than the complex photodissociation threshold, which is found to be 41740 ± 200 cm(-1) (239.6±1.2 nm). This last threshold corresponds to the photodissociation giving rise to an unexcited isoprene molecule. The second channel, with threshold shifted to the blue by 1480 ± 280 cm(-1), corresponds to dissociation with formation of rovibrationally excited isoprene. A third channel was observed at wavelengths up to 243 nm with excitation below the upper photodissociation threshold. This channel is attributed to dissociation with the formation of a bound O atom C(5)H(8)-O(2) + hv → C(5)H(8)-O(2)((3)Δ(u)) → C(5)H(8)O + O and/or to dissociation of O(2) with borrowing of the lacking energy from incompletely cooled complex internal degrees of freedom C(5)H(8)*-O(2) + hv → C(5)H(8)*-O(2)((3)Δ(u)) → C(5)H(8) + O + O. The kinetic energy of the O atoms arising in two other observed channels corresponds to O atoms produced by photodissociation of molecular oxygen in the excited a (1)Δ(g) and b (1)Σ(g)(+) singlet states as the precursors. This indicates the formation of singlet oxygen O(2)(a (1)Δ(g)) and O(2)(b (1)Σ(g)(+)) after excitation of the C(5)H(8)-O(2) complex. Cooperative excitation of the complex with a simultaneous change of the spin of both partners (1)X-(3)O(2) + hν → (3)X-(1)O(2) → (3)X + (1)O(2) is suggested as a source of singlet oxygen O(2)(a (1)Δ(g)) and O(2)(b (1)Σ(g)(+)). This cooperative excitation is in agreement with little or no vibrational excitation of O(2)(a (1)Δ(g)), produced from the C(5)H(8)-O(2) complex as studied in the current paper as well as from the C(3)H(6)-O(2) and CH(3)I-O(2) complexes reported in our previous paper [Baklanov et al., J. Chem. Phys. 126, 124316 (2007)]. The formation of O(2)(a (1)Δ(g)) from C(5)H(8)-O(2) was observed at λ(pump) = 213-277 nm with the yield going down towards the long wavelength edge of this interval. This spectral profile is interpreted as the red-side wing of the band of a cooperative transition (1)X-(3)O(2) + hν → (3)X(T(2))-(1)O(2)(a (1)Δ(g)) in the C(5)H(8)-O(2) complex.
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Affiliation(s)
- Konstantin V Vidma
- Institute for Molecules and Materials, Radboud University Nijmegen, Heyendaalseweg 135, 6525 ED Nijmegen, The Netherlands
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30
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Horke DA, Roberts GM, Lecointre J, Verlet JRR. Velocity-map imaging at low extraction fields. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2012; 83:063101. [PMID: 22755609 DOI: 10.1063/1.4724311] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We present a velocity-map imaging (VMI) setup for photoelectron imaging that utilizes low electric extraction fields. This avoids any complications that could arise from electrostatic interactions between the extraction field and the molecular properties that are probed and has a minimal effect on the trajectory of ions in ion beam experiments. By using an attractive potential supplied to the detector, and keeping the electrodes at ground (zero) potential, we show that fringe fields between the VMI arrangement and the vacuum chamber can be eliminated, which is important in experiments on ions.
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Affiliation(s)
- Daniel A Horke
- Department of Chemistry, University of Durham, South Road, DH1 3LE Durham, United Kingdom
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31
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Sanz-Sanz C, Richings GW, Worth GA. Dynamic Stark control: model studies based on the photodissociation of IBr. Faraday Discuss 2012; 153:275-91; discussion 293-319. [PMID: 22452087 DOI: 10.1039/c1fd00039j] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The Stark effect is produced when a static field alters molecular states. When the field applied is time dependent, the process is known as the dynamic Stark effect. Of particular interest for the control of molecular dynamics is the Non-Resonant Dynamic Stark Effect (NRDSE), in which the time dependent field is unable to effect a one-photon excitation. The intermediate strength laser pulse instead shapes the potential energy surfaces (PES) and so guides the evolution of the system. A prototype control scheme uses the NRDSE to change the topography of PES in regions where they intersect, thus providing control over photochemistry. Following earlier experimental work, in this paper we study the NRDSE on a new 3 state model of the IBr molecule to gain insight into the mechanism of control at the avoided crossing that governs the branching ratio of the photodissociation.
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32
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Murdock D, Crow MB, Ritchie GAD, Ashfold MNR. UV photodissociation dynamics of iodobenzene: Effects of fluorination. J Chem Phys 2012; 136:124313. [DOI: 10.1063/1.3696892] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
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33
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Wenge AM, Schmaunz A, Kensy U, Dick B. Photodissociation dynamics of tert-butylnitrite following excitation to the S1 and S2 states. A study by velocity-map ion-imaging and 3D-REMPI spectroscopy. Phys Chem Chem Phys 2012; 14:7076-89. [DOI: 10.1039/c2cp40349h] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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34
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Zaouris DK, Wenge AM, Murdock D, Oliver TAA, Richmond G, Ritchie GAD, Dixon RN, Ashfold MNR. Conformer specific dissociation dynamics of iodocyclohexane studied by velocity map imaging. J Chem Phys 2011; 135:094312. [PMID: 21913768 DOI: 10.1063/1.3628682] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The photodissociation dynamics of iodocyclohexane has been studied using velocity map imaging following excitation at many wavelengths within its A-band (230 ≤ λ ≤ 305 nm). This molecule exists in two conformations (axial and equatorial), and one aim of the present experiment was to explore the extent to which conformer-specific fragmentation dynamics could be distinguished. Ground (I) and spin-orbit excited (I∗) state iodine atom products were monitored by 2 + 1 resonance enhanced multiphoton ionization, and total kinetic energy release (TKER) spectra and angular distributions derived from analysis of images recorded at all wavelengths studied. TKER spectra obtained at the longer excitation wavelengths show two distinct components, which can be attributed to the two conformers and the different ways in which these partition the excess energy upon C-I bond fission. Companion calculations based on a simple impulsive model suggest that dissociation of the equatorial (axial) conformer preferentially yields vibrationally (rotationally) excited cyclohexyl co-fragments. Both I and I∗ products are detected at the longest parent absorption wavelength (λ ∼ 305 nm), and both sets of products show recoil anisotropy parameters, β > 1, implying prompt dissociation following excitation via a transition whose dipole moment is aligned parallel to the C-I bond. The quantum yield for forming I∗ products, Φ(I∗), has been determined by time resolved infrared diode laser absorption methods to be 0.14 ± 0.02 (at λ = 248 nm) and 0.22 ± 0.05 (at λ = 266 nm). Electronic structure calculations indicate that the bulk of the A-band absorption is associated with transition to the 4A(') state, and that the (majority) I atom products arise via non-adiabatic transfer from the 4A(') potential energy surface (PES) via conical intersection(s) with one or more PESs correlating with ground state products.
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Affiliation(s)
- D K Zaouris
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, United Kingdom
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35
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Scott Hopkins W, Mackenzie SR. Communication: Imaging wavefunctions in dissociative photoionization. J Chem Phys 2011; 135:081104. [DOI: 10.1063/1.3632103] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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36
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Crider PE, Harrison AW, Neumark DM. Two- and three-body photodissociation dynamics of diiodobromide (I2Br−) anion. J Chem Phys 2011; 134:134306. [DOI: 10.1063/1.3571474] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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37
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Zhang Y, Yang CH, Wu SM, van Roij A, van der Zande WJ, Parker DH, Yang X. A large aperture magnification lens for velocity map imaging. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2011; 82:013301. [PMID: 21280819 DOI: 10.1063/1.3505491] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We have designed and implemented a large aperture electrostatic Einzel lens that magnifies the images of low energy ions or electrons in a standard velocity map imaging apparatus by up to a factor of 5 while allowing the normal use of the apparatus (without blocking any part of the detector). The field strength in the interaction region remains reasonably constant with or without magnification, and the lens can be used in the normal "crush" mode or with any of the different variants of the "slicing" mode. We have characterized the performance of the lens by imaging ion recoil due to two-photon resonant three-photon ionization [(2+1) REMPI] of O((3)P(2)) atoms and by imaging slow NO molecules from the near-threshold photodissociation of the NO-Ar van der Waals complex.
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Affiliation(s)
- Yongwei Zhang
- Radboud University Nijmegen, Institute for Molecules and Materials, The Netherlands
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38
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Sage AG, Oliver TAA, Murdock D, Crow MB, Ritchie GAD, Harvey JN, Ashfold MNR. nσ* and πσ* excited states in aryl halide photochemistry: a comprehensive study of the UV photodissociation dynamics of iodobenzene. Phys Chem Chem Phys 2011; 13:8075-93. [DOI: 10.1039/c0cp02390f] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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39
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Affiliation(s)
- Dave Townsend
- School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, United Kingdom, and Steacie Institute for Molecular Sciences, National Research Council of Canada, 100 Sussex Drive, Ottawa, Ontario, K1A 0R6, Canada
| | - Benjamin J. Sussman
- School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, United Kingdom, and Steacie Institute for Molecular Sciences, National Research Council of Canada, 100 Sussex Drive, Ottawa, Ontario, K1A 0R6, Canada
| | - Albert Stolow
- School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, United Kingdom, and Steacie Institute for Molecular Sciences, National Research Council of Canada, 100 Sussex Drive, Ottawa, Ontario, K1A 0R6, Canada
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40
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Horvath S, Pitzer RM, McCoy AB. Theoretical investigations of the time-resolved photodissociation dynamics of IBr(-). J Phys Chem A 2010; 114:11337-46. [PMID: 20712343 DOI: 10.1021/jp1051529] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The role of laser pulse width as well as other quantum mechanical effects in the interpretation of the observed time-resolved photoelectron spectra (TRPES) of IBr(-) are investigated using conditions that are chosen to reproduce those used for the experimental study of Mabbs et al. [ J. Chem. Phys. 2005 , 122 , 174305 ]. In that study, it was shown that one could correlate shifts in the frequency of the maximum in signal as a function of time to differences between the potential energies of the electronic states that are accessed by the pump and probe lasers. While this classical picture is attractive, it is based on a single trajectory with an initial I-Br separation that is ∼0.3 Å longer than the equilibrium value. In addition, it does not include the role of the pulse widths and other possible quantum effects. In the present work, the six lowest energy electronic states of IBr(-) were calculated at the MR-SO-CISD/aug-cc-pVDZ level of theory/basis set as a function of the I-Br distance. The TRPES of IBr(-) were calculated in three pulse regimes: an infinitesimally short pulse, an intermediate pulse that has a temporal full width at half-maximum (fwhm) of 300 fs, which was chosen to match the experimental value, and one that is 3 times longer than the experimental value. The resulting spectra are qualitatively different, and the sources of these differences are discussed. The intermediate pulse provides very good agreement with experiment with the introduction of no adjustable parameters. The origins of the features of the experimental signal are discussed in terms of this fully quantum mechanical picture.
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Affiliation(s)
- Samantha Horvath
- Department of Chemistry, The Ohio State University, Columbus, Ohio 43210, USA
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41
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Sage AG, Oliver TA, Dixon RN, Ashfold MN. Velocity map imaging studies of the photodissociation of H2O+cations. Mol Phys 2010. [DOI: 10.1080/00268971003596177] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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42
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Hopkins WS, Hamilton SM, McNaughter PD, Mackenzie SR. VUV photodissociation dynamics of diatomic gold, Au2: A velocity map imaging study at 157nm. Chem Phys Lett 2009. [DOI: 10.1016/j.cplett.2009.10.072] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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43
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Ogi Y, Kohguchi H, Niu D, Ohshimo K, Suzuki T. Super-Resolution Photoelectron Imaging with Real-Time Subpixelation by Field Programmable Gate Array and Its Application to NO and Benzene Photoionization. J Phys Chem A 2009; 113:14536-44. [PMID: 19817387 DOI: 10.1021/jp9039995] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yoshihiro Ogi
- Chemical Dynamics Laboratory, RIKEN Advanced Science Institute, 2-1 Hirosawa, Wako 351-0198, Japan
| | - Hiroshi Kohguchi
- Chemical Dynamics Laboratory, RIKEN Advanced Science Institute, 2-1 Hirosawa, Wako 351-0198, Japan
| | - Dongmei Niu
- Chemical Dynamics Laboratory, RIKEN Advanced Science Institute, 2-1 Hirosawa, Wako 351-0198, Japan
| | - Keijiro Ohshimo
- Chemical Dynamics Laboratory, RIKEN Advanced Science Institute, 2-1 Hirosawa, Wako 351-0198, Japan
| | - Toshinori Suzuki
- Chemical Dynamics Laboratory, RIKEN Advanced Science Institute, 2-1 Hirosawa, Wako 351-0198, Japan
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44
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Chichinin AI, Gericke KH, Kauczok S, Maul C. Imaging chemical reactions – 3D velocity mapping. INT REV PHYS CHEM 2009. [DOI: 10.1080/01442350903235045] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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45
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Wilkinson I, de Miranda MP, Whitaker BJ. Photodissociation of NO2 in the (2) (2)B2 state: the O((1)D2) dissociation channel. J Chem Phys 2009; 131:054308. [PMID: 19673563 DOI: 10.1063/1.3194286] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Direct current slice and crush velocity map imaging has been used to probe the photodissociation dynamics of nitrogen dioxide above the second dissociation limit. The paper is a companion to a previous publication [J. Chem. Phys. 128, 164318 (2008)] in which we reported results for the O((3)P(J)) + NO((2)Pi(Omega)) adiabatic product channel. Here we examine the O((1)D(2)) + NO((2)Pi(Omega)) diabatic product channel at similar excitation energies. Using one- and two-color imaging experiments to observe the velocity distributions of state selected NO fragments and O atoms, respectively, we are able to build a detailed picture of the dissociation dynamics. We show that by combining the information obtained from velocity map imaging studies with mass-resolved resonantly enhanced multiphoton ionization spectroscopy it is possible to interpret and fully assign the NO images. By recording two-color images of the O((1)D(2)) photofragments with different polarization combinations of the pump and probe laser fields we also measure the orbital angular momentum alignment in the atomic fragment. We find that the entire O((1)D(2)) photofragment distribution is similarly aligned with most of the population in the M(J) = +/-1 magnetic sublevels. The similarity of the fragment polarizations is interpreted as a signature of all of the O((1)D(2)) atoms being formed via the same avoided crossing. At the photolysis energy of 5.479 52 eV we find that the NO fragments are preferentially formed in v = 1 and that the vibrationally excited fragments exhibit a bimodal rotational distribution. This is in contrast to the unimodal rotational profile of the NO fragments in v = 0. We discuss these observations in terms of the calculated topology of the adiabatic potential energy surfaces and attribute the vibrational inversion and rotational bimodality of the v = 1 fragments to the symmetric stretch and bending motion generated on excitation to the (2) (2)B(2) state.
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Affiliation(s)
- Iain Wilkinson
- School of Chemistry, University of Leeds, Leeds LS2 9JT, United Kingdom
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Abstract
Photofragment spectroscopy is combined with imaging techniques and time-resolved measurements of photoions and photoelectrons to explore the predissociation dynamics of weakly bound molecules. Recent experimental advances include measurements of pair-correlated distributions, in which energy disposal in one cofragment is correlated with a state-selected level of the other fragment, and femtosecond pump-probe experiments, in some cases with coincidence detection. An application in which coincident measurements are carried out in the molecular frame is also described. To illustrate these state-selective and time-resolved techniques, we review two recent applications: (a) the photoinitiated dissociation of the covalently bound NO dimer on the ground and excited electronic states and the role of state couplings and (b) the state-selected vibrational predissociation of hydrogen-bonded acetylene dimers with HCl (acid) and ammonia (base) and the importance of angular momentum constraints. We highlight the crucial role of theoretical models in interpreting results.
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Affiliation(s)
- Hanna Reisler
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482
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Webb AD, Nahler NH, Ashfold MNR. Imaging studies of the photodissociation of NH3+ and ND3+ cations. J Phys Chem A 2009; 113:3773-8. [PMID: 19216561 DOI: 10.1021/jp808854d] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Velocity map ion imaging methods have been used to study the photofragmentation dynamics of state-selected NH3+ and ND3+ cations. The cations were prepared in selected nu2+ bending vibrational levels of the ground (x2A'') electronic state by two-photon resonant, three-photon ionization of NH3(ND3), via several different nu2' levels of the and ' Rydberg states. Subsequent excitation to the A2E state by absorption of a 207.6 nm photon resulted in N-H(D) bond fission and NH2+(ND2+) fragment ion formation. These fragments exhibit isotropic recoil velocity distributions, which peak at low kinetic energy but extend to the maximum allowed by energy conservation. Such findings accord with conclusions from earlier electron induced photoionization and photoelectron-photoion coincidence studies of NH3 at similar total energies (defined relative to the ground-state neutral) and, as previously, can be rationalized in terms of excitation to the Jahn-Teller distorted state, rapid radiationless transfer via one or more conical intersections linking the and state potential energy surfaces (PESs) and subsequent unimolecular decay on the latter PES. Weak NH2+ and NH+ fragment ion signals are also observed when exciting with the ionization laser only; imaging these fragment ions provides some insights into their likely formation mechanisms.
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Affiliation(s)
- Alexander D Webb
- School of Chemistry, University of Bristol, Bristol, BS8 1TS, UK
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Reisler H, Krylov AI. Interacting Rydberg and valence states in radicals and molecules: experimental and theoretical studies. INT REV PHYS CHEM 2009. [DOI: 10.1080/01442350902989170] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Sheps L, Miller EM, Lineberger WC. Photoelectron spectroscopy of small IBr[sup −](CO[sub 2])[sub n] (n=0–3) cluster anions. J Chem Phys 2009; 131:064304. [DOI: 10.1063/1.3200941] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Wilkinson I, Whitaker BJ. Photodissociation of NO2 in the (2)B22 state: A slice imaging study and reinterpretation of previous results. J Chem Phys 2008; 129:154312. [DOI: 10.1063/1.2994735] [Citation(s) in RCA: 21] [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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