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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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2
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Fournier M, Lopez GV, Spiliotis AK, Casey TA, Rakitzis TP, Chandler DW. Alignment and dissociation of electronically excited molecular hydrogen with intense laser fields. Mol Phys 2021. [DOI: 10.1080/00268976.2020.1778200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Martin Fournier
- Combustion Research Facility, Sandia National Laboratories, Livermore, CA, USA
| | - Gary V. Lopez
- Combustion Research Facility, Sandia National Laboratories, Livermore, CA, USA
| | - Alexandros K. Spiliotis
- Department of Physics, Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas, University of Crete, Crete, Greece
| | - Tiernan A. Casey
- Combustion Research Facility, Sandia National Laboratories, Livermore, CA, USA
| | - T. Peter Rakitzis
- Department of Physics, Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas, University of Crete, Crete, Greece
| | - David W. Chandler
- Combustion Research Facility, Sandia National Laboratories, Livermore, CA, USA
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Bianchini RH, Roman MJ, Costen ML, McKendrick KG. Real-space laser-induced fluorescence imaging applied to gas-liquid interfacial scattering. J Chem Phys 2019. [DOI: 10.1063/1.5110517] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Robert H. Bianchini
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - Maksymilian J. Roman
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - Matthew L. Costen
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - Kenneth G. McKendrick
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
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Abujarada S, Walton AS, Thomas AG, Chohan UK, Koehler SPK. Adsorption site, orientation and alignment of NO adsorbed on Au(100) using 3D-velocity map imaging, X-ray photoelectron spectroscopy and density functional theory. Phys Chem Chem Phys 2019; 21:10939-10946. [PMID: 31093639 DOI: 10.1039/c9cp01963d] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Nitric oxide adsorption on a Au(100) single crystal has been investigated to identify the type of adsorption, the adsorption site, and the orientation and alignment of the adsorbed NO relative to the surface. This was done using a combination of 3D-surface velocity map imaging, near-ambient pressure X-ray photoelectron spectroscopy, and density functional theory. NO was observed to be molecularly adsorbed on gold at ∼200 K. Very narrow angular distributions and cold rotational distributions of photodesorbed NO indicate that NO adsorbs on high-symmetry sites on the Au crystal, with the N-O bond axis close to the surface normal. Our density functional theory calculations show that NO preferentially adsorbs on the symmetric bridge (2f) site, which ensures efficient overlap of the NO π* orbital with the orbitals on the two neighbouring Au atoms, and with the N-O bond axis aligned along the surface normal, in agreement with our conclusions from the rotational state distributions. The combination of XPS, which reveals the orientation of NO on gold, with 3D-surface velocity map imaging and density functional theory thus allowed us to determine the adsorption site, orientation and alignment of nitric oxide adsorbed on Au(100).
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Affiliation(s)
- Saada Abujarada
- School of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK and Photon Science Institute, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Alex S Walton
- School of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK and Photon Science Institute, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Andrew G Thomas
- Photon Science Institute, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK and School of Materials, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Urslaan K Chohan
- School of Materials, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Sven P K Koehler
- School of Science and the Environment, Manchester Metropolitan University, Chester Street, Manchester, M1 5GD, UK.
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Kregel SJ, Thurston GK, Zhou J, Garand E. A multi-plate velocity-map imaging design for high-resolution photoelectron spectroscopy. J Chem Phys 2017; 147:094201. [DOI: 10.1063/1.4996011] [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
Affiliation(s)
- Steven J. Kregel
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave., Madison, Wisconsin 53706, USA
| | - Glen K. Thurston
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave., Madison, Wisconsin 53706, USA
| | - Jia Zhou
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave., Madison, Wisconsin 53706, USA
| | - Etienne Garand
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave., Madison, Wisconsin 53706, USA
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Lopez GV, Fournier M, Jankunas J, Spiliotis AK, Rakitzis TP, Chandler DW. Alignment of the hydrogen molecule under intense laser fields. J Chem Phys 2017; 147:013948. [PMID: 28688451 DOI: 10.1063/1.4989935] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Alignment of the electronically excited E,F state of the H2 molecule is studied using the velocity mapping imaging technique. Photofragment images of H+ due to the dissociation mechanism that follows the 2-photon excitation into the (E,F; ν = 0, J = 0) electronic state show a strong dependence on laser intensity, which is attributed to the high polarizability anisotropy of the H2 (E,F) state. We observe a marked structure in the angular distribution, which we explain as the interference between the prepared J = 0 and Stark-mixed J = 2 rovibrational states of H2, as the laser intensity increases. Quantification of these effects allows us to extract the polarizability anisotropy of the H2 (E,F J = 0) state yielding a value of 312 ± 82 a.u. (46 Å3). By comparison, CS2 has 10 Å3, I2 has 7 Å3, and hydrochlorothiazide (C7H8ClN3O4S2) has about 25 Å3 meaning that we have created the most easily aligned molecule ever measured, by creating a mixed superposition state that is highly anisotropic in its polarizability.
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Affiliation(s)
- Gary V Lopez
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94550, USA
| | - Martin Fournier
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94550, USA
| | - Justin Jankunas
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94550, USA
| | - Alexandros K Spiliotis
- Department of Physics, University of Crete, and Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas, Heraklion, Crete 70013, Greece
| | - T Peter Rakitzis
- Department of Physics, University of Crete, and Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas, Heraklion, Crete 70013, Greece
| | - David W Chandler
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94550, USA
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Abujarada S, AlSalem H, Chohan UK, Draper GL, Koehler SPK. Photodesorption of NO from Au(100) using 3D surface-velocity map imaging. J Chem Phys 2016; 145:184201. [DOI: 10.1063/1.4967248] [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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Hadden DJ, Messider TM, Leng JG, Greaves SJ. Note: Velocity map imaging the scattering plane of gas surface collisions. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2016; 87:106104. [PMID: 27802734 DOI: 10.1063/1.4965970] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The ability of gas-surface dynamics studies to resolve the velocity distribution of the scattered species in the 2D scattering plane has been limited by technical capabilities and only a few different approaches have been explored in recent years. In comparison, gas-phase scattering studies have been transformed by the near ubiquitous use of velocity map imaging. We describe an innovative means of introducing a dielectric surface within the electric field of a typical velocity map imaging experiment. The retention of optimum velocity mapping conditions was validated by measurements of iodomethane-d3 photodissociation and SIMION calculations. To demonstrate the system's capabilities, the velocity distributions of ammonia molecules scattered from a polytetrafluoroethylene surface have been measured for multiple product rotational states.
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Affiliation(s)
- D J Hadden
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - T M Messider
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - J G Leng
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - S J Greaves
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
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Reid M, Green V, Koehler SPK. Near-threshold photodissociation dynamics of CHCl3. Phys Chem Chem Phys 2014; 16:6068-74. [PMID: 24557156 DOI: 10.1039/c3cp55348e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Energy- and angle-resolved photofragment distributions for ground-state Cl ((2)P3/2) and spin-orbit excited Cl* ((2)P1/2) have been recorded using the velocity map imaging technique after photodissociation of chloroform at wavelengths of 193 and ∼235 nm. Translational energy distributions are rather broad and peak between 0.6 and 1.0 eV. The spin-orbit branching ratios [Cl*]/[Cl] are 1 and 0.3 at 193 and 235 nm, respectively, indicating the involvement of two or more excited state surfaces. Considering the anisotropy parameters and branching ratios collectively, we conclude that the reaction at 193 nm takes place predominantly on the (1)Q1 surface, while the (3)Q1 surface gains importance at lower dissociation energies around 235 nm.
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Affiliation(s)
- Mike Reid
- School of Chemistry, The University of Manchester, Manchester M13 9PL, UK.
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Parry IS, Hermes AC, Kartouzian A, Mackenzie SR. Imaging the photodissociation dynamics of neutral metal clusters: copper dimer, Cu2, and copper oxide, CuO. Phys Chem Chem Phys 2014; 16:458-66. [DOI: 10.1039/c3cp53214c] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Kershis MD, Wilson DP, White MG, John JJ, Nomerotski A, Brouard M, Lee JWL, Vallance C, Turchetta R. Exploring surface photoreaction dynamics using pixel imaging mass spectrometry (PImMS). J Chem Phys 2013; 139:084202. [DOI: 10.1063/1.4818997] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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