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Jaquet R, Khoma MV. Investigation of non-adiabatic effects for the ro-vibrational spectrum of H3+: the use of a single potential energy surface with geometry-dependent nuclear masses. Mol Phys 2018. [DOI: 10.1080/00268976.2018.1464225] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- Ralph Jaquet
- Theoretische Chemie, Universität Siegen , Siegen, Germany
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Jaquet R, Khoma MV. Investigation of Nonadiabatic Effects for the Vibrational Spectrum of a Triatomic Molecule: The Use of a Single Potential Energy Surface with Distance-Dependent Masses for H 3. J Phys Chem A 2017; 121:7016-7030. [PMID: 28820589 DOI: 10.1021/acs.jpca.7b04703] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
On the basis of first-principles, the influence of nonadiabatic effects on the vibrational bound states of H3+ has been investigated using distance-dependent reduced masses and only one single potential energy surface. For these new vibrational calculations, potentials based on explicitly correlated wave functions are used where, in addition, adiabatic corrections and relativistic contributions are taken into account. For the first time, several different fully distance-dependent reduced mass surfaces in three dimensions have been incorporated in the vibrational calculations.
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Affiliation(s)
- Ralph Jaquet
- Theoretische Chemie, Universität Siegen , D-57068 Siegen, Germany
| | - Mykhaylo V Khoma
- Theoretische Chemie, Universität Siegen , D-57068 Siegen, Germany
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Jaquet R. Investigation of the highest bound ro-vibrational states of H+3, DH+2, HD+2, D+3, and T+3: use of a non-direct product basis to compute the highest allowedJ> 0 states. Mol Phys 2013. [DOI: 10.1080/00268976.2013.818727] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Jaquet R, Carrington T. Using a Nondirect Product Basis to Compute J > 0 Rovibrational States of H3+. J Phys Chem A 2013; 117:9493-500. [DOI: 10.1021/jp312027s] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ralph Jaquet
- Theoretische Chemie, Universität Siegen, D-57068 Siegen, Germany
| | - Tucker Carrington
- Chemistry Department, Queens’s University, Kingston, Ontario, K7L
3N6, Canada
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Affiliation(s)
- Héctor Medel Cobaxin
- Groupe de Spectrométrie Moléculaire
et
Atmosphérique (UMR CNRS 7331), U.F.R. Sciences Exactes et Naturelles, University of Reims Champagne-Ardenne, Moulin de la
Housse B.P. 1039, F-51687 Reims Cedex 2, France
| | - Alexander Alijah
- Groupe de Spectrométrie Moléculaire
et
Atmosphérique (UMR CNRS 7331), U.F.R. Sciences Exactes et Naturelles, University of Reims Champagne-Ardenne, Moulin de la
Housse B.P. 1039, F-51687 Reims Cedex 2, France
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Polyansky OL, Alijah A, Zobov NF, Mizus II, Ovsyannikov RI, Tennyson J, Lodi L, Szidarovszky T, Császár AG. Spectroscopy of H3+ based on a new high-accuracy global potential energy surface. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2012; 370:5014-5027. [PMID: 23028150 DOI: 10.1098/rsta.2012.0014] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The molecular ion H(3)(+) is the simplest polyatomic and poly-electronic molecular system, and its spectrum constitutes an important benchmark for which precise answers can be obtained ab initio from the equations of quantum mechanics. Significant progress in the computation of the ro-vibrational spectrum of H(3)(+) is discussed. A new, global potential energy surface (PES) based on ab initio points computed with an average accuracy of 0.01 cm(-1) relative to the non-relativistic limit has recently been constructed. An analytical representation of these points is provided, exhibiting a standard deviation of 0.097 cm(-1). Problems with earlier fits are discussed. The new PES is used for the computation of transition frequencies. Recently measured lines at visible wavelengths combined with previously determined infrared ro-vibrational data show that an accuracy of the order of 0.1 cm(-1) is achieved by these computations. In order to achieve this degree of accuracy, relativistic, adiabatic and non-adiabatic effects must be properly accounted for. The accuracy of these calculations facilitates the reassignment of some measured lines, further reducing the standard deviation between experiment and theory.
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Affiliation(s)
- Oleg L Polyansky
- Institute of Applied Physics, Russian Academy of Sciences, Ulyanov Street 46, Nizhny Novgorod 603950, Russia.
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Berg M, Wolf A, Petrignani A. Visible transitions from ground state H3+ measured with high-sensitivity action spectroscopy. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2012; 370:5028-5040. [PMID: 23028151 DOI: 10.1098/rsta.2012.0017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We report on the recent observation of new spectral lines of cold H(3)(+) ions lying well in the visible spectral region. Transitions from the two lowest ro-vibrational levels to final levels up to 16,700 cm(-1), almost half way to the dissociation limit, have been measured, involving up to eight vibrational quanta. The observed transitions are more than six orders of magnitude less intense than the v(2)(1) fundamental band and yet another order of magnitude weaker than reached by previous sensitive action spectroscopy in the near-infrared region. The measurements were carried out in a cryogenic 22-pole ion trap with H(3)(+) ions cooled to their lowest rotational levels by helium buffer gas. Laser-induced chemical reactions lead to the formation of ArH(+) ions detected with single-ion sensitivity. These visible measurements, together with the previous near-infrared measurements, have helped to further develop empirically corrected calculations and have provided essential benchmarks for new ab initio calculations that now reach a spectroscopic accuracy of 0.1 cm(-1) on average up to the highest observed transition. Highly sensitive action spectroscopy and the attained high-accuracy predictions will enable us to find and measure transitions even further into the visible region of H(3)(+), paving the way towards the dissociation limit.
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Affiliation(s)
- Max Berg
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
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Adamowicz L, Pavanello M. Progress in calculating the potential energy surface of H3+. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2012; 370:5001-5013. [PMID: 23028149 DOI: 10.1098/rsta.2012.0101] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The most accurate electronic structure calculations are performed using wave function expansions in terms of basis functions explicitly dependent on the inter-electron distances. In our recent work, we use such basis functions to calculate a highly accurate potential energy surface (PES) for the H(3)(+) ion. The functions are explicitly correlated Gaussians, which include inter-electron distances in the exponent. Key to obtaining the high accuracy in the calculations has been the use of the analytical energy gradient determined with respect to the Gaussian exponential parameters in the minimization of the Rayleigh-Ritz variational energy functional. The effective elimination of linear dependences between the basis functions and the automatic adjustment of the positions of the Gaussian centres to the changing molecular geometry of the system are the keys to the success of the computational procedure. After adiabatic and relativistic corrections are added to the PES and with an effective accounting of the non-adiabatic effects in the calculation of the rotational/vibrational states, the experimental H(3)(+) rovibrational spectrum is reproduced at the 0.1 cm(-1) accuracy level up to 16,600 cm(-1) above the ground state.
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Affiliation(s)
- Ludwik Adamowicz
- Department of Chemistry, University of Arizona, Tucson, AZ 85721, USA
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Jaquet R, Khoma MV. Nonadiabatic investigations of ro-vibrational frequencies within the systems , H2, and prospects for : use of distance-dependent effective masses. Mol Phys 2012. [DOI: 10.1080/00268976.2012.671969] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Jaquet R, Khoma MV. A systematic investigation of the ground state potential energy surface of H3+. J Chem Phys 2012; 136:154307. [PMID: 22519326 DOI: 10.1063/1.4704123] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Based on different ab initio electronic structure calculations (CI-R12 and Gaussian Geminals) of the Born-Oppenheimer electronic energy E(BO) of H(3)(+) from high to highest quality, we build up a potential energy surface which represents a highly reliable form of the topology of the whole potential region, locally and globally. We use the CI-R12 method in order to get within reasonable CPU-time a relatively dense grid of energy points. We demonstrate that CI-R12 is good enough to give an accurate surface, i.e., Gaussian Geminals are not absolutely necessary. For different types of potential energy surface fits, we performed variational calculations of all bound vibrational states, including resonances above the dissociation limit, for total angular momentum J = 0. We clarify the differences between different fits of the energy to various functional forms of the potential surface. Small rms-values (<1 cm(-1)) of the fit do not provide precise information about the interpolatory behaviour of the fit functions.
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Affiliation(s)
- Ralph Jaquet
- Theoretische Chemie, Universität Siegen, D-57068 Siegen, Germany.
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Pavanello M, Adamowicz L, Alijah A, Zobov NF, Mizus II, Polyansky OL, Tennyson J, Szidarovszky T, Császár AG, Berg M, Petrignani A, Wolf A. Precision measurements and computations of transition energies in rotationally cold triatomic hydrogen ions up to the midvisible spectral range. PHYSICAL REVIEW LETTERS 2012; 108:023002. [PMID: 22324677 DOI: 10.1103/physrevlett.108.023002] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2011] [Indexed: 05/22/2023]
Abstract
First-principles computations and experimental measurements of transition energies are carried out for vibrational overtone lines of the triatomic hydrogen ion H(3)(+) corresponding to floppy vibrations high above the barrier to linearity. Action spectroscopy is improved to detect extremely weak visible-light spectral lines on cold trapped H(3)(+) ions. A highly accurate potential surface is obtained from variational calculations using explicitly correlated Gaussian wave function expansions. After nonadiabatic corrections, the floppy H(3)(+) vibrational spectrum is reproduced at the 0.1 cm(-1) level up to 16600 cm(-1).
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Affiliation(s)
- Michele Pavanello
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, Arizona 85721, USA.
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Sutcliffe BT. An analysis of the role of the Born--Oppenheimer approximation in calculating rotational--vibrational interactions in molecules. Theor Chem Acc 2011. [DOI: 10.1007/s00214-011-0953-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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