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Heays AN, Lewis BR, de Oliveira N, Ubachs W. The spin-forbidden vacuum-ultraviolet absorption spectrum of 14N 15N. J Chem Phys 2019; 151:224305. [PMID: 31837671 DOI: 10.1063/1.5130206] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Photoabsorption spectra of 14N15N were recorded at high resolution with a vacuum-ultraviolet Fourier-transform spectrometer fed by synchrotron radiation in the range of 81-100 nm. The combination of high column density (3 × 1017 cm-2) and low temperature (98 K) allowed for the recording of weak spin-forbidden absorption bands' exciting levels of triplet character. The triplet states borrow intensity from 1Πu states of Rydberg and valence character while causing their predissociation. New predissociation linewidths and molecular constants are obtained for the states C3Πu(v = 7, 8, 14, 15, 16, 21), G3Πu(v = 0, 1, 4), and F3Πu(v = 0). The positions and widths of these levels are shown to be well-predicted by a coupled-Schrödinger equation model with empirical parameters based on experimental data on 14N2 and 15N2 triplet levels.
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Affiliation(s)
- A N Heays
- Department of Physics and Astronomy, and LaserLaB, VU University, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - B R Lewis
- Research School of Physics and Engineering, The Australian National University, Canberra, Australian Capital Territory 0200, Australia
| | - N de Oliveira
- Synchrotron Soleil, Orme des Merisiers, St. Aubin, BP 48, 91192 Gif sur Yvette Cedex, France
| | - W Ubachs
- Department of Physics and Astronomy, and LaserLaB, VU University, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
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2
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Holzmeier F, Bello RY, Hervé M, Achner A, Baumann TM, Meyer M, Finetti P, Di Fraia M, Gauthier D, Roussel E, Plekan O, Richter R, Prince KC, Callegari C, Bachau H, Palacios A, Martín F, Dowek D. Control of H_{2} Dissociative Ionization in the Nonlinear Regime Using Vacuum Ultraviolet Free-Electron Laser Pulses. PHYSICAL REVIEW LETTERS 2018; 121:103002. [PMID: 30240272 DOI: 10.1103/physrevlett.121.103002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Indexed: 06/08/2023]
Abstract
The role of the nuclear degrees of freedom in nonlinear two-photon single ionization of H_{2} molecules interacting with short and intense vacuum ultraviolet pulses is investigated, both experimentally and theoretically, by selecting single resonant vibronic intermediate neutral states. This high selectivity relies on the narrow bandwidth and tunability of the pulses generated at the FERMI free-electron laser. A sustained enhancement of dissociative ionization, which even exceeds nondissociative ionization, is observed and controlled as one selects progressively higher vibronic states. With the help of ab initio calculations for increasing pulse durations, the photoelectron and ion energy spectra obtained with velocity map imaging allow us to identify new photoionization pathways. With pulses of the order of 100 fs, the experiment probes a timescale that lies between that of ultrafast dynamical processes and that of steady state excitations.
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Affiliation(s)
- F Holzmeier
- Institut des Sciences Moléculaires d'Orsay CNRS, Université Paris-Sud, Université Paris-Saclay, 91405 Orsay Cedex, France
- Synchrotron SOLEIL, 91192 Gif-sur-Yvette, France
| | - R Y Bello
- Departamento de Química, Módulo 13, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - M Hervé
- Institut des Sciences Moléculaires d'Orsay CNRS, Université Paris-Sud, Université Paris-Saclay, 91405 Orsay Cedex, France
| | - A Achner
- European XFEL GmbH, 22869 Schenefeld, Germany
| | - T M Baumann
- European XFEL GmbH, 22869 Schenefeld, Germany
| | - M Meyer
- European XFEL GmbH, 22869 Schenefeld, Germany
| | - P Finetti
- Elettra-Sincrotrone Trieste, 34149 Basovizza, Trieste, Italy
| | - M Di Fraia
- Elettra-Sincrotrone Trieste, 34149 Basovizza, Trieste, Italy
| | - D Gauthier
- Elettra-Sincrotrone Trieste, 34149 Basovizza, Trieste, Italy
| | - E Roussel
- Elettra-Sincrotrone Trieste, 34149 Basovizza, Trieste, Italy
| | - O Plekan
- Elettra-Sincrotrone Trieste, 34149 Basovizza, Trieste, Italy
| | - R Richter
- Elettra-Sincrotrone Trieste, 34149 Basovizza, Trieste, Italy
| | - K C Prince
- Elettra-Sincrotrone Trieste, 34149 Basovizza, Trieste, Italy
| | - C Callegari
- Elettra-Sincrotrone Trieste, 34149 Basovizza, Trieste, Italy
| | - H Bachau
- Centre des Lasers Intenses et Applications (UMR 5107 du CNRS-CEA-Université de Bordeaux), 351 Cours de la Libération, 33405 Talence cedex, France
| | - A Palacios
- Departamento de Química, Módulo 13, Universidad Autónoma de Madrid, 28049 Madrid, Spain
- Institute for Advanced Research in Chemical Sciences (IAdChem), Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - F Martín
- Departamento de Química, Módulo 13, Universidad Autónoma de Madrid, 28049 Madrid, Spain
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), Cantoblanco, 28049 Madrid, Spain
- Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - D Dowek
- Institut des Sciences Moléculaires d'Orsay CNRS, Université Paris-Sud, Université Paris-Saclay, 91405 Orsay Cedex, France
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3
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Shingledecker CN, Herbst E. A general method for the inclusion of radiation chemistry in astrochemical models. Phys Chem Chem Phys 2018; 20:5359-5367. [PMID: 29067367 DOI: 10.1039/c7cp05901a] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this paper, we propose a general formalism that allows for the estimation of radiolysis decomposition pathways and rate coefficients suitable for use in astrochemical models, with a focus on solid phase chemistry. Such a theory can help increase the connection between laboratory astrophysics experiments and astrochemical models by providing a means for modelers to incorporate radiation chemistry into chemical networks. The general method proposed here is targeted particularly at the majority of species now included in chemical networks for which little radiochemical data exist; however, the method can also be used as a starting point for considering better studied species. We here apply our theory to the irradiation of H2O ice and compare the results with previous experimental data.
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Jansen P, Bethlem HL, Ubachs W. Perspective: Tipping the scales: Search for drifting constants from molecular spectra. J Chem Phys 2014; 140:010901. [DOI: 10.1063/1.4853735] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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5
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de Lange A, Dickenson GD, Salumbides EJ, Ubachs W, de Oliveira N, Joyeux D, Nahon L. VUV Fourier-transform absorption study of the Lyman and Werner bands in D2. J Chem Phys 2012; 136:234310. [PMID: 22779596 DOI: 10.1063/1.4726457] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
An extensive survey of the D(2) absorption spectrum has been performed with the high-resolution VUV Fourier-transform spectrometer employing synchrotron radiation. The frequency range of 90,000-119,000 cm(-1) covers the full depth of the potential wells of the B (1)Σ(u)(+), B' (1)Σ(u)(+), and C (1)Π(u) electronic states up to the D(1s) + D(2l) dissociation limit. Improved level energies of rovibrational levels have been determined up to respectively v = 51, v = 13, and v = 20. Highest resolution is achieved by probing absorption in a molecular gas jet with slit geometry, as well as in a liquid helium cooled static gas cell, resulting in line widths of ≈0.35 cm(-1). Extended calibration methods are employed to extract line positions of D(2) lines at absolute accuracies of 0.03 cm(-1). The D (1)Π(u) and B'' (1)Σ(u)(+) electronic states correlate with the D(1s) + D(3l]) dissociation limit, but support a few vibrational levels below the second dissociation limit, respectively, v = 0-3 and v = 0-1, and are also included in the presented study. The complete set of resulting level energies is the most comprehensive and accurate data set for D(2). The observations are compared with previous studies, both experimental and theoretical.
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Affiliation(s)
- Arno de Lange
- Institute for Lasers, Life and Biophotonics, VU University, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands.
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Glass-Maujean M, Jungen C, Roudjane M, Tchang-Brillet WÜL. Theory of vibronic interactions in D2 and H2: A comparison between multichannel-quantum-defect and coupled-equation approaches. J Chem Phys 2011; 134:204305. [DOI: 10.1063/1.3593274] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
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7
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Affiliation(s)
- Ch Seiler
- ETH Zurich, Laboratory of Physical Chemistry, Wolfgang Pauli-Str. 10, Zurich, Switzerland
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Bailly D, Salumbides E, Vervloet M, Ubachs W. Accurate level energies in the EF1, GK1, H1, B1, , B′1, , , J1Δgstates of H2. Mol Phys 2010. [DOI: 10.1080/00268970903413350] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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9
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King JA, Webb JK, Murphy MT, Carswell RF. Stringent null constraint on cosmological evolution of the proton-to-electron mass ratio. PHYSICAL REVIEW LETTERS 2008; 101:251304. [PMID: 19113692 DOI: 10.1103/physrevlett.101.251304] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2008] [Indexed: 05/27/2023]
Abstract
We present a strong constraint on variation of the proton-to-electron mass ratio mu over cosmological time scales using molecular hydrogen transitions in optical quasar spectra. Using high quality spectra of quasars Q0405-443, Q0347-383, and Q0528-250, variation in micro relative to the present day value is limited to Deltamicro/micro=(2.6+/-3.0)x10;{-6}. We reduce systematic errors compared to previous works by substantially improving the spectral wavelength calibration method and by fitting absorption profiles to the forest of hydrogen Lyman alpha transitions surrounding each H2 transition. Our results are consistent with no variation, and inconsistent with a previous approximately 4sigma detection of mu variation involving Q0405-443 and Q0347-383. If the results of this work and those suggesting that alpha may be varying are both correct, then this would tend to disfavor certain grand unification models.
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Affiliation(s)
- Julian A King
- School of Physics, University of New South Wales, Sydney, NSW 2052, Australia
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Salumbides EJ, Bailly D, Khramov A, Wolf AL, Eikema KSE, Vervloet M, Ubachs W. Improved laboratory values of the H2 Lyman and Werner lines for constraining time variation of the proton-to-electron mass ratio. PHYSICAL REVIEW LETTERS 2008; 101:223001. [PMID: 19113480 DOI: 10.1103/physrevlett.101.223001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2008] [Indexed: 05/27/2023]
Abstract
Two distinct high-accuracy laboratory spectroscopic investigations of the H2 molecule are reported. Anchor lines in the EF1Sigmag+-X1Sigmag+ system are calibrated by two-photon deep-UV Doppler-free spectroscopy, while independent Fourier-transform spectroscopic measurements are performed that yield accurate spacings in the B1Sigmau+-EF1Sigmag+ and I1Pig-C1Piu systems. From combination differences accurate transition wavelengths for the B-X Lyman and the C-X Werner lines can be determined with accuracies better than approximately 5 x 10(-9), representing a major improvement over existing values. This metrology provides a practically exact database to extract a possible variation of the proton-to-electron mass ratio based on H2 lines in high-redshift objects. Moreover, it forms a rationale for equipping a future class of telescopes, carrying 30-40 m dishes, with novel spectrometers of higher resolving powers.
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Affiliation(s)
- E J Salumbides
- Laser Centre, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
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11
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Roudjane M, Ivanov T, Vieitez M, de Lange C, Tchang-Brillet W, Ubachs W. Extreme ultraviolet laser calibration of D_2Lyman and Werner transitions. Mol Phys 2008. [DOI: 10.1080/00268970802056045] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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12
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Ivanov TI, Roudjane M, Vieitez MO, de Lange CA, Tchang-Brillet WUL, Ubachs W. HD as a probe for detecting mass variation on a cosmological time scale. PHYSICAL REVIEW LETTERS 2008; 100:093007. [PMID: 18352708 DOI: 10.1103/physrevlett.100.093007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2007] [Indexed: 05/26/2023]
Abstract
The strong electronic absorption systems of the B1 Sigma u+-X1 Sigma g+ Lyman and the C1Pi u-X1 Sigma g+ Werner bands can be used to probe possible mass-variation effects on a cosmological time scale from spectra observed at high redshift, not only in H2 but also in the second most abundant hydrogen isotopomer HD. High resolution laboratory determination of the most prominent HD lines at extreme ultraviolet wavelengths is performed at an accuracy of delta lambda/lambda approximately 5 x 10(-8), forming a database for comparison with astrophysical data. Sensitivity coefficients Ki = d ln lambda i/d ln mu are determined for HD from quantum ab initio calculations as a function of the proton-electron mass ratio mu. Strategies to deduce possible effects beyond first-order baryon/lepton mass ratio deviations are discussed.
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Affiliation(s)
- T I Ivanov
- Laser Centre, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
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13
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Reinhold E, Buning R, Hollenstein U, Ivanchik A, Petitjean P, Ubachs W. Indication of a cosmological variation of the proton-electron mass ratio based on laboratory measurement and reanalysis of H2 spectra. PHYSICAL REVIEW LETTERS 2006; 96:151101. [PMID: 16712142 DOI: 10.1103/physrevlett.96.151101] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2005] [Revised: 10/06/2005] [Indexed: 05/09/2023]
Abstract
Based on highly accurate laboratory measurements of Lyman bands of H2 and an updated representation of the structure of the ground X 1sigma(g)+ and excited B 1sigma(u)+ and C 1pi(u) states, a new set of sensitivity coefficients K(i) is derived for all lines in the H2 spectrum, representing the dependence of their transition wavelengths on a possible variation of the proton-electron mass ratio mu = m(p)/m(e). Included are local perturbation effects between B and C levels and adiabatic corrections. The new wavelengths and K(i) factors are used to compare with a recent set of highly accurate H2 spectral lines observed in the Q 0347-383 and Q 0405-443 quasars, yielding a fractional change in the mass ratio of deltamu/mu = (2.4 +/- 0.6) x 10(-5) for a weighted fit and deltamu/mu = (2.0 +/- 0.6) x 10(-5) for an unweighted fit. This result indicates, at a 3.5sigma confidence level, that mu could have decreased in the past 12 Gyr.
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Affiliation(s)
- E Reinhold
- Laser Centre, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
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