1
|
Tóbiás R, Diouf ML, Cozijn FMJ, Ubachs W, Császár AG. All paths lead to hubs in the spectroscopic networks of water isotopologues H 216O and H 218O. Commun Chem 2024; 7:34. [PMID: 38365971 PMCID: PMC10873357 DOI: 10.1038/s42004-024-01103-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 01/08/2024] [Indexed: 02/18/2024] Open
Abstract
Network theory has fundamentally transformed our comprehension of complex systems, catalyzing significant advances across various domains of science and technology. In spectroscopic networks, hubs are the quantum states involved in the largest number of transitions. Here, utilizing network paths probed via precision metrology, absolute energies have been deduced, with at least 10-digit accuracy, for almost 200 hubs in the experimental spectroscopic networks of H216O and H218O. These hubs, lying on the ground vibrational states of both species and the bending fundamental of H216O, are involved in tens of thousands of observed transitions. Relying on the same hubs and other states, benchmark-quality line lists have been assembled, which supersede and improve, by three orders of magnitude, the accuracy of the massive amount of data reported in hundreds of papers dealing with Doppler-limited spectroscopy. Due to the omnipresence of water, these ultraprecise line lists could be applied to calibrate high-resolution spectra and serve ongoing and upcoming space missions.
Collapse
Affiliation(s)
- Roland Tóbiás
- Laboratory of Molecular Structure and Dynamics, Institute of Chemistry, ELTE Eötvös Loránd University and HUN-REN-ELTE Complex Chemical Systems Research Group, H-1117 Budapest, Pázmány Péter sétány 1/A, Hungary
| | - Meissa L Diouf
- Department of Physics and Astronomy, LaserLaB, Vrije Universiteit, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Frank M J Cozijn
- Department of Physics and Astronomy, LaserLaB, Vrije Universiteit, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Wim Ubachs
- Department of Physics and Astronomy, LaserLaB, Vrije Universiteit, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands.
| | - Attila G Császár
- Laboratory of Molecular Structure and Dynamics, Institute of Chemistry, ELTE Eötvös Loránd University and HUN-REN-ELTE Complex Chemical Systems Research Group, H-1117 Budapest, Pázmány Péter sétány 1/A, Hungary.
| |
Collapse
|
2
|
Salem J, Tóbiás R, Császár AG, Mogren Al-Mogren M, Jaidane NE, Hochlaf M. Temperature-Dependent Line-Broadening Effects in CO 2 Caused by Ar. Chemphyschem 2024; 25:e202300467. [PMID: 37916391 DOI: 10.1002/cphc.202300467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Revised: 10/28/2023] [Accepted: 10/30/2023] [Indexed: 11/03/2023]
Abstract
This computational study of line-broadening effects is based on an accurate, analytical representation of the intermonomer potential energy surface (PES) of the CO2 ⋅ Ar van der Waals (vdW) complex. The PES is employed to compute collisional broadening coefficients for rovibrational lines of CO2 perturbed by Ar. The semiclassical computations are performed using the modified Robert-Bonamy approach, including real and imaginary terms, and the exact trajectory model. The lines investigated are in the 10001←00011, 01101←00001, 00011←00001, and 00031←00001 vibrational bands and the computations are repeated at multiple temperatures. The computed results are in good agreement with the available experimental values, validating both the intermonomer PES developed and the methodology used. For lines in the 01101←00001 band of CO2 , temperature-dependent Ar-broadening coefficients are reported for the first time. The parameters presented should prove useful, among other applications, for the accurate experimental determination of CO2 and Ar abundances in planetary atmospheres.
Collapse
Affiliation(s)
- Jamel Salem
- Université de Gafsa, Laboratoire Technologie, Energie, Matériaux Innovants, Faculté des Sciences, Sidi Ahmed Zarroug -, 2112, Gafsa, Tunisia
| | - Roland Tóbiás
- Laboratory of Molecular Structure and Dynamics, Institute of Chemistry, ELTE Eötvös Loránd University, Pázmány Péter sétány 1/A, H-1117, Budapest, Hungary
| | - Attila G Császár
- Laboratory of Molecular Structure and Dynamics, Institute of Chemistry, ELTE Eötvös Loránd University, Pázmány Péter sétány 1/A, H-1117, Budapest, Hungary
- HUN-REN-ELTE Complex Chemical Systems Research Group, H-1518, Budapest 112, P.O. Box 32, Hungary
| | - Muneerah Mogren Al-Mogren
- Department of Chemistry, College of Sciences, King Saud University, P.O. Box 2455, Riyadh, 11451, Saudi Arabia
| | - Nejm-Edine Jaidane
- Laboratoire de Spectroscopie Atomique, Moléculaire et Applications LSAMA, Université de Tunis Al Manar, Tunis, Tunisia
| | - Majdi Hochlaf
- Université Gustave Eiffel, COSYS/IMSE, 5 Bd Descartes, 77454, Champs sur Marne, France
| |
Collapse
|
3
|
Tóbiás R, Simkó I, Császár AG. Unusual Dynamics and Vibrational Fingerprints of van der Waals Dimers Formed by Linear Molecules and Rare-Gas Atoms. J Chem Theory Comput 2023. [PMID: 38032107 DOI: 10.1021/acs.jctc.3c00914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2023]
Abstract
Detailed structural, dynamical, and vibrational analyses have been performed for systems composed of linear triatomic molecules solvated by a single rare-gas atom, He, Ne, or Ar. Among the chromophores of these van der Waals (vdW) dimers, there are four neutral molecules (CO2, CS2, N2O, and OCS) and six molecular cations (HHe2+, HNe2+, HAr2+, HHeNe+, HHeAr+, and HNeAr+), both of apolar and polar nature. Following the exploration of bonding preferences, high-level four-dimensional (4D) potential energy surfaces (PESs) have been developed for 24 vdW dimers, keeping the two intramonomer bond lengths fixed. For these 24 complexes, over 1500 bound vibrational states have been obtained via quasi-variational nuclear-motion computations, employing exact kinetic-energy operators together with the accurate 4D PESs and their 2D/3D cuts. The reduced-dimensional (2D to 4D) dimer models have been compared with full-dimensional (6D) ones in the cases of the neutral CO2·Ar and charged HHe2+·He dimers, corroborating the high accuracy of the 2D to 4D vibrational energies. The reduced-dimensional models suggest that (a) while the equilibrium structures are T-shaped and planar, the effective ground-state structures are nonplanar, (b) certain bound states belong to collinear molecular structures, even when they are not minima, (c) the vdW vibrations are heavily mixed and many states have amplitudes corresponding to both the T-shaped and collinear structures, (d) there are a few dimers, for which even some of the vdW fundamentals lie above the first dissociation limit, and (e) the vdW vibrations are almost fully decoupled from the intramonomer bending motion.
Collapse
Affiliation(s)
- Roland Tóbiás
- HUN-REN-ELTE Complex Chemical Systems Research Group, P.O. Box 32, H-1518 Budapest 112, Hungary
| | - Irén Simkó
- Hevesy György PhD School of Chemistry, ELTE Eötvös Loránd University, Pázmány Péter sétány 1/A, H-1117 Budapest, Hungary
- Institute of Chemistry, ELTE Eötvös Loránd University, Pázmány Péter sétány 1/A, H-1117 Budapest, Hungary
| | - Attila G Császár
- HUN-REN-ELTE Complex Chemical Systems Research Group, P.O. Box 32, H-1518 Budapest 112, Hungary
- Institute of Chemistry, ELTE Eötvös Loránd University, Pázmány Péter sétány 1/A, H-1117 Budapest, Hungary
| |
Collapse
|
4
|
Diouf ML, Tóbiás R, Cozijn FMJ, Salumbides EJ, Fábri C, Puzzarini C, Császár AG, Ubachs W. Parity-pair-mixing effects in nonlinear spectroscopy of HDO. Opt Express 2022; 30:46040-46059. [PMID: 36558568 DOI: 10.1364/oe.474525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 10/27/2022] [Indexed: 06/17/2023]
Abstract
A non-linear spectroscopic study of the HDO molecule is performed in the wavelength range of 1.36-1.42 μm using noise-immune cavity-enhanced optical-heterodyne molecular spectroscopy (NICE-OHMS). More than 100 rovibrational Lamb dips are recorded, with an experimental precision of 2-20 kHz, related to the first overtone of the O-H stretch fundamental of HD16O and HD18O. Significant perturbations, including distortions, shifts, and splittings, have been observed for a number of Lamb dips. These spectral perturbations are traced back to an AC-Stark effect, arising due to the strong laser field applied in all saturation-spectroscopy experiments. The AC-Stark effect mixes parity pairs, that is pairs of rovibrational states whose assignment differs solely in the Kc quantum number, where Kc is part of the standard J K a,K c asymmetric-top rotational label. Parity-pair mixing seems to be especially large for parity pairs with Ka ≥ 3, whereby their energy splittings become as small as a few MHz, resulting in multi-component asymmetric Lamb-dip profiles of gradually increasing complexity. These complex profiles often include crossover resonances. This effect is well known in saturation spectroscopy, but has not been reported in combination with parity-pair mixing. Parity-pair mixing is not seen in H2 16O and H2 18O, because their parity pairs correspond to ortho and para nuclear-spin isomers, whose interaction is prohibited. Despite the frequency shifts observed for HD16O and HD18O, the absolute accuracy of the detected transitions still exceeds that achievable by Doppler-limited techniques.
Collapse
|
5
|
Diouf ML, Tóbiás R, van der Schaaf TS, Cozijn FMJ, Salumbides EJ, Császár AG, Ubachs W. Ultraprecise relative energies in the (2 0 0) vibrational band of H 216O. Mol Phys 2022. [DOI: 10.1080/00268976.2022.2050430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Meissa L. Diouf
- Department of Physics and Astronomy, LaserLaB, Vrije Universiteit, Amsterdam, The Netherlands
| | - Roland Tóbiás
- Laboratory of Molecular Structure and Dynamics, Institute of Chemistry, ELTE Eötvös Loránd University and ELKH-ELTE Complex Chemical Systems Research Group, Budapest, Hungary
| | - Tom S. van der Schaaf
- Department of Physics and Astronomy, LaserLaB, Vrije Universiteit, Amsterdam, The Netherlands
| | - Frank M. J. Cozijn
- Department of Physics and Astronomy, LaserLaB, Vrije Universiteit, Amsterdam, The Netherlands
| | - Edcel J. Salumbides
- Department of Physics and Astronomy, LaserLaB, Vrije Universiteit, Amsterdam, The Netherlands
| | - Attila G. Császár
- Laboratory of Molecular Structure and Dynamics, Institute of Chemistry, ELTE Eötvös Loránd University and ELKH-ELTE Complex Chemical Systems Research Group, Budapest, Hungary
| | - Wim Ubachs
- Department of Physics and Astronomy, LaserLaB, Vrije Universiteit, Amsterdam, The Netherlands
| |
Collapse
|
6
|
Tóbiás R, Árendás P, Császár AG. Normal-Mode Vibrational Analysis of Weakly Bound Oligomers at Constrained Stationary Points of Arbitrary Order. J Chem Theory Comput 2022; 18:1788-1798. [PMID: 35201747 DOI: 10.1021/acs.jctc.1c01148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Following the full realization of the importance of noncovalent interactions, finding and characterizing stationary points (SP), of various order, for weakly bound oligomers have become important tasks for computational chemists. An efficient algorithm and an associated computer code, called oligoCGO, are described, facilitating constrained geometry optimization of oligomers of arbitrary structure and complexity and normal-mode vibrational analysis at nonstationary geometries. To minimize the adverse effects of nonzero forces on harmonic vibrational analyses at constrained stationary points (cSP), two residual gradient correction (RGC) schemes are proposed. RGC1, for which a rigorous justification is given, is based on ignoring the remaining forces in internal-coordinate space. RGC2 modifies the geometry of the cSP in a single Newton step and recalculates the Cartesian Hessian at this updated geometry. As demonstrated by 10 examples related to the water-water, water-methane, and methane-methane dimers as well as the methane trimer, without RGC the harmonic analysis of cSPs may result in even qualitatively incorrect results when compared to reference values obtained at the nearby unconstrained SPs (uSP). Both RGC protocols work exceedingly well, and the corrected harmonic wavenumbers of the cSPs are very close to their uSP counterparts.
Collapse
Affiliation(s)
- Roland Tóbiás
- Institute of Chemistry, ELTE Eötvös Loránd University, Budapest 1117, Hungary.,MTA-ELTE Complex Chemical Systems Research Group, Budapest 1117, Hungary
| | - Péter Árendás
- Institute of Chemistry, ELTE Eötvös Loránd University, Budapest 1117, Hungary.,MTA-ELTE Complex Chemical Systems Research Group, Budapest 1117, Hungary.,Budapest Business School, Budapest 1149, Hungary
| | - Attila G Császár
- Institute of Chemistry, ELTE Eötvös Loránd University, Budapest 1117, Hungary.,MTA-ELTE Complex Chemical Systems Research Group, Budapest 1117, Hungary
| |
Collapse
|
7
|
Abstract
Several significant improvements are proposed to the computational molecular spectroscopy protocol MARVEL (Measured Active Rotational-Vibrational Energy Levels) facilitating the inversion of a large set of measured rovibrational transitions to energy levels. The most important algorithmic changes include the use of groups of transitions, blocked by their estimated experimental (source segment) uncertainties, an inversion and weighted least-squares refinement procedure based on sequential addition of blocks of decreasing accuracy, the introduction of spectroscopic cycles into the refinement process, automated recalibration, synchronization of the combination difference relations to reduce residual uncertainties in the resulting dataset of empirical (MARVEL) energy levels, and improved classification of the lines and energy levels based on their accuracy and dependability. The resulting protocol, through handling a large number of measurements of similar accuracy, retains, or even improves upon, the best reported uncertainties of the spectroscopic transitions employed. To show its advantages, the extended MARVEL protocol is applied for the analysis of the complete set of highly accurate H216O transition measurements. As a result, almost 300 highly accurate energy levels of H216O are reported in the energy range of 0-6000 cm-1. Out of the 15 vibrational bands involved in accurately measured rovibrational transitions, the following three have definitely highly accurate empirical rovibrational energies of 8-10 digits of accuracy: (v1v2v3) = (0 0 0), (0 1 0), and (0 2 0), where v1, v2, and v3 stand for the symmetric stretch, bend, and antisymmetric stretch vibrational quantum numbers. The dataset of experimental rovibrational transitions and empirical rovibrational energy levels assembled during this study, both with improved uncertainties, is considerably larger and more accurate than the best previous datasets.
Collapse
Affiliation(s)
- Roland Tóbiás
- Laboratory of Molecular Structure and Dynamics, Institute of Chemistry, ELTE Eötvös Loránd University and MTA-ELTE Complex Chemical Systems Research Group, P.O. Box 32, H-1518 Budapest 112, Hungary
| | | | | | | |
Collapse
|
8
|
Metz MP, Szalewicz K, Sarka J, Tóbiás R, Császár AG, Mátyus E. Molecular dimers of methane clathrates: ab initio potential energy surfaces and variational vibrational states. Phys Chem Chem Phys 2019; 21:13504-13525. [DOI: 10.1039/c9cp00993k] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Motivated by the energetic and environmental relevance of methane clathrates, highly accurate ab initio potential energy surfaces (PESs) have been developed for the three possible dimers of the methane and water molecules: (H2O)2, CH4·H2O, and (CH4)2.
Collapse
Affiliation(s)
- Michael P. Metz
- Department of Physics and Astronomy
- University of Delaware
- Newark
- USA
| | | | - János Sarka
- Department of Chemistry and Biochemistry
- Texas Tech University
- Lubbock
- USA
| | - Roland Tóbiás
- Institute of Chemistry
- ELTE Eötvös Loránd University
- Budapest
- Hungary
- MTA-ELTE Complex Chemical Systems Research Group
| | - Attila G. Császár
- Institute of Chemistry
- ELTE Eötvös Loránd University
- Budapest
- Hungary
- MTA-ELTE Complex Chemical Systems Research Group
| | - Edit Mátyus
- Institute of Chemistry
- ELTE Eötvös Loránd University
- Budapest
- Hungary
| |
Collapse
|
9
|
Tóbiás R, Császár AG, Gyevi-Nagy L, Tasi G. Definitive thermochemistry and kinetics of the interconversions among conformers of n-butane and n-pentane. J Comput Chem 2018; 39:424-437. [PMID: 29239472 DOI: 10.1002/jcc.25130] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 10/27/2017] [Accepted: 10/31/2017] [Indexed: 11/09/2022]
Abstract
The focal-point analysis (FPA) technique is used for the definitive characterization of conformational interconversion parameters, including activation energy barriers, activation free energies, and kinetic rate coefficients at 298 K, of two n-alkanes, n-butane, and n-pentane, yielding the first complete analysis of their interconversion kinetics. The FPA implementation developed in this study is based on geometry optimizations and harmonic frequency computations carried out with density functional theory methods and single-point energy computations up to the CCSD(T) level of electronic structure theory using atom-centered Gaussian basis sets as large as cc-pV5Z. The anharmonic vibrational computations are carried out, at the MP2/6-31G* level of theory. Reflecting the convergence behavior of the Gibbs free-energy terms and the interconversion parameters, well-defined uncertainties, mostly neglected in previous theoretical studies, are provided. Finally, the effect of these uncertainties on the concentrations of the conformers of n-butane and n-pentane is examined via a global Monte-Carlo uncertainty analysis. © 2017 Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- Roland Tóbiás
- MTA-ELTE Complex Chemical Systems Research Group, H-1518 Budapest 112, P.O. Box 32, Hungary
| | - Attila G Császár
- MTA-ELTE Complex Chemical Systems Research Group, H-1518 Budapest 112, P.O. Box 32, Hungary.,Laboratory of Molecular Structure and Dynamics, Institute of Chemistry, Eötvös Loránd University, H-1117 Budapest, Pázmány Péter sétány 1/A, Hungary
| | - László Gyevi-Nagy
- Department of Physical Chemistry and Materials Science, University of Szeged, H-6720 Szeged, Rerrich B. tér 1, Hungary
| | - Gyula Tasi
- Department of Applied and Environmental Chemistry, University of Szeged, H-6720 Szeged, Rerrich B. tér 1, Hungary
| |
Collapse
|