1
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Guan Y, Chen Q, Varandas AJC. Accurate diabatization based on combined-hyperbolic-inverse-power-representation: 1,2 2A' states of BeH2. J Chem Phys 2024; 160:154105. [PMID: 38624109 DOI: 10.1063/5.0200732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2024] [Accepted: 03/28/2024] [Indexed: 04/17/2024] Open
Abstract
A diabatic potential energy matrix (DPEM) for the two lowest states of BeH2+ has been constructed using the combined-hyperbolic-inverse-power-representation (CHIPR) method. By imposing symmetry constraints on the coefficients of polynomials, the complete nuclear permutation inversion symmetry is correctly preserved in the CHIPR functional form. The symmetrized CHIPR functional form is then used in the diabatization by ansatz procedure. The ab initio energies are reproduced with satisfactory accuracy. In addition, the CHIPR-based DPEM also reproduces the local topology of a conical intersection. Future work will focus on a complete four-state diabatic representation with emphasis on the long-range interactions and spin-orbit couplings, which will enable accurate quantum scattering calculations for the Be+(2P) + H2 → BeH+(X1Σ+) + H(2S) reaction.
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Affiliation(s)
- Yafu Guan
- State Key Laboratory of Molecular Reaction Dynamics and Center for Theoretical Computational Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, People's Republic of China
| | - Qun Chen
- State Key Laboratory of Molecular Reaction Dynamics and Center for Theoretical Computational Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, People's Republic of China
| | - António J C Varandas
- School of Physics and Physical Engineering, Qufu Normal University, 273165 Qufu, People's Republic of China
- Department of Physics, Universidade Federal do Espírito Santo, 29075-910 Vitória, Brazil
- Department of Chemistry and Chemistry Centre, University of Coimbra, 3004-535 Coimbra, Portugal
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2
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Rocha CMR, Linnartz H, Varandas AJC. Reconciling spectroscopy with dynamics in global potential energy surfaces: the case of the astrophysically relevant SiC_{2}. J Chem Phys 2022; 157:104301. [DOI: 10.1063/5.0096364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
SiC_{2} is a fascinating molecule due to its unusual bonding and astrophysical importance. In this work, we report the first global potential energy surface (PES) for ground-state SiC_{2} using the combined-hyperbolic-inverse-power-representation (CHIPR) method and accurate ab initio energies. The calibration grid data is obtained via a general dual-level protocol developed afresh herein that entails both coupled-cluster and multireference configuration interaction energies jointly extrapolated to the complete basis set limit. Such an approach is specially devised to recover much of the spectroscopy from the PES, while still permitting a proper fragmentation of the system to allow for reaction dynamics studies. Besides describing accurately the valence strongly-bound region that includes both the cyclic global minimum and isomerization barriers, the final analytic PES form is shown to properly reproduce dissociation energies,diatomic potentials, and long-range interactions at all asymptotic channels, in addition to naturally reflect the correct permutational symmetry of the potential. Bound vibrational state calculations have been carried out, unveiling an excellent match of the available experimental data on c-SiC_{2}(^{1}A_{1}). To further exploit the global nature of the PES, exploratory quasi-classical trajectory calculations for the endothermic C2 +Si → SiC+C reaction are also performed, yielding thermalized rate coefficients for temperatures up to 5000 K. The results hint for the prominence of this reaction in the innermost layers of the circumstellar envelopes around carbon-rich stars, thence conceivably playing therein a key contribution to the gas-phase formation of SiC, and eventually, solid SiC dust.
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Affiliation(s)
| | | | - António JC Varandas
- Departament of Chemistry, University of Coimbra Coimbra Chemistry Centre, Portugal
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3
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Varandas AJC. From six to eight Π-electron bare rings of group-XIV elements and beyond: can planarity be deciphered from the "quasi-molecules" they embed? Phys Chem Chem Phys 2022; 24:8488-8507. [PMID: 35343978 DOI: 10.1039/d1cp04130d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ab initio molecular orbital theory is used to study the structures of six and eight π-electron bare rings of group-XIV elements, and even larger [n]annulenes up to C18H18, including some of their mono-, di-, tri-, and tetra-anions. While some of the above rings are planar, others are nonplanar. A much spotlighted case is cyclo-octatetraene (C8H8), which is predicted to be nonplanar together with its heavier group-XIV analogues Si8H8 and Ge8H8, with the solely planar members of its family having the stoichiometric formulas C4Si4H8 and C4Ge4H8. A similar situation arises with the six π-electron bare rings, where benzene and substituted ones up to C3Si3H6 or so are planar, while others are not. However, the explanations encountered in the literature find support in ab initio calculations for such species, often rationalized from distinct calculated features. Using second-order Møller-Plesset perturbation theory and, when affordable (particularly tetratomics, which may allow even higher levels), the coupled-cluster method including single, double, and perturbative triple excitations, a common rationale is suggested based on a novel concept of quasi-molecules or the (3+4)-atom partition scheme. Any criticism of tautology is therefore avoided. The same analysis has also been successfully applied to even larger [n]annulenes, to their mixed family members involving silicon and germanium atoms, and to the C18 carbon ring. Furthermore, it has been extended to annulene anions to check the criteria of the popular Hückel rule for planarity and aromaticity. Exploratory work on cycloarenes is also reported. Besides a partial study of the involved potential energy surfaces, equilibrium geometries and harmonic vibrational frequencies have been calculated anew, for both the parent and the actual prototypes of the quasi-molecules.
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Affiliation(s)
- A J C Varandas
- School of Physics and Physical Engineering, Qufu Normal University, 273165 Qufu, China.,Department of Physics, Universidade Federal do Esp rito Santo, 29075-910 Vitória, Brazil.,Department of Chemistry, and Chemistry Centre, University of Coimbra, 3004-535 Coimbra, Portugal.
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4
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Li X, Qin Z, Li J, Liu L. An accurate NH 2(X 2A′′) CHIPR potential energy surface via extrapolation to the complete basis set limit and dynamics of the N( 2D) + H 2(X 1Σ+g) reaction. Phys Chem Chem Phys 2022; 24:26564-26574. [DOI: 10.1039/d2cp01961b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
An accurate CHIPR potential energy surface for NH2(X2A′′) is structured to study the N(2D) + H2(X1Σ+g) reaction using the time-dependent wave packet and quasi-classical trajectory method.
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Affiliation(s)
- Ximing Li
- School of Energy and Power Engineering, Shandong University, 250061, Jinan, China
| | - Zhi Qin
- School of Energy and Power Engineering, Shandong University, 250061, Jinan, China
- Optics and Thermal Radiation Research Center, Institute of Frontier and Interdisciplinary Science, Shandong University, 266237, Qingdao, China
| | - Jing Li
- School of Physics and Physical Engineering, Qufu Normal University, 273165, Qufu, China
| | - Linhua Liu
- School of Energy and Power Engineering, Shandong University, 250061, Jinan, China
- Optics and Thermal Radiation Research Center, Institute of Frontier and Interdisciplinary Science, Shandong University, 266237, Qingdao, China
- School of Energy Science and Engineering, Harbin Institute of Technology, 150001, Harbin, China
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5
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Chen G, Qin Z, Li J, Liu L. A global CHIPR potential energy surface of PH 2(X 2B 1) via extrapolation to the complete basis set limit and the dynamics of P( 2D) + H 2(X 1Σ+g) → PH(X 3Σ −) + H( 2S). Phys Chem Chem Phys 2022; 24:19371-19381. [DOI: 10.1039/d2cp02690b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
A global PEC of the ground state PH2 was constructed using the CHIPR method based on accurate MRCI(Q)/CBS(T, Q) energy points. The ICS and k(T) of P(2D) + H2(X1Σ+g) → PH(X3Σ−) + H(2S) were calculated based on the QCT method.
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Affiliation(s)
- Guangan Chen
- School of Energy and Power Engineering, Shandong University, 250061, Jinan, China
| | - Zhi Qin
- School of Energy and Power Engineering, Shandong University, 250061, Jinan, China
- Optics and Thermal Radiation Research Center, Institute of Frontier and Interdisciplinary Science, Shandong University, 266237, Qingdao, China
| | - Jing Li
- School of Physics and Physical Engineering, Qufu Normal University, 273165, Qufu, China
| | - Linhua Liu
- School of Energy and Power Engineering, Shandong University, 250061, Jinan, China
- Optics and Thermal Radiation Research Center, Institute of Frontier and Interdisciplinary Science, Shandong University, 266237, Qingdao, China
- School of Energy Science and Engineering, Harbin Institute of Technology, 150001, Harbin, China
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6
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Ghosh S, Sharma R, Adhikari S, Varandas AJC. Dynamical calculations of O( 3P) + OH( 2Π) reaction on the CHIPR potential energy surface using the fully coupled time-dependent wave-packet approach in hyperspherical coordinates. Phys Chem Chem Phys 2021; 23:21784-21796. [PMID: 34550126 DOI: 10.1039/d1cp02488d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We have carried out quantum dynamics calculations for the O + OH → H + O2 reaction on the CHIPR [A. J. C. Varandas, J. Chem. Phys., 2013, 138, 134117] potential energy surface (PES) for ground state HO2 using the fully coupled 3D time-dependent wavepacket formalism [S. Adhikari and A. J. C. Varandas, Comput. Phys. Commun., 2013, 184, 270] in hyperspherical coordinates. Reaction probabilities for J > 0 are calculated for different initial rotational states of the OH radical (v = 0; j = 0, 1). State-to-state as well as total integral cross sections and rate-coefficients are evaluated and compared with previous theoretical calculations and available experimental studies. Using the rate constant for the forward (hereinafter considered to be H + O2 → O + OH) and backward (O + OH → H + O2) reactions of this reactive system, the equilibrium constant of the reversible process [H + O2 ⇌ O + OH] is calculated as a function of temperature and compared with previous experimental measurements.
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Affiliation(s)
- Sandip Ghosh
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A & 2B Raja S. C. Mullick Road, Jadavpur, Kolkata-700032, West Bengal, India.
| | - Rahul Sharma
- Department of Chemistry, St. Xaviers' College, Kolkata-700016, West Bengal, India
| | - Satrajit Adhikari
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A & 2B Raja S. C. Mullick Road, Jadavpur, Kolkata-700032, West Bengal, India.
| | - António J C Varandas
- School of Physics and Physical Engineering, Qufu Normal University, 273165 Qufu, China.,Department of Physics, Universidade Federal do Espírito Santo, 29075-910 Victória, Brazil.,Departamento de Qumica, and Centro de Qumica, Universidade de Coimbra, 3004-535 Coimbra, Portugal.
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7
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Varandas AJC. Extrapolation in quantum chemistry: Insights on energetics and reaction dynamics. JOURNAL OF THEORETICAL & COMPUTATIONAL CHEMISTRY 2020. [DOI: 10.1142/s0219633620300013] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Since there is no exact solution for problems in physics and chemistry, extrapolation methods may assume a key role in quantitative quantum chemistry. Two topics where it bears considerable impact are addressed, both at the heart of computational quantum chemistry: electronic structure and reaction dynamics. In the first, the problem of extrapolating the energy obtained by solving the electronic Schrödinger equation to the limit of the complete one-electron basis set is addressed. With the uniform-singlet-and-triplet-extrapolation (USTE) scheme at the focal point, the emphasis is on recent updates covering from the energy itself to other molecular properties. The second topic refers to extrapolation of quantum mechanical reactive scattering probabilities from zero total angular momentum to any of the values that it may assume when running quasiclassical trajectories, QCT/QM-[Formula: see text]J. With the extrapolation guided in both cases by physically motivated asymptotic theories, realism is seeked by avoiding unsecure jumps into the unknown. Although, mostly review oriented, a few issues are addressed for the first time here and there. Prospects for future work conclude the overview.
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Affiliation(s)
- A. J. C. Varandas
- School of Physics and Physical Engineering, Qufu Normal University, Qufu 273165, P. R. China
- Department of Physics, Universidade Federal do Espírito Santo, Vitória 29075-910, Brazil
- Department of Chemistry and Chemistry Centre, University of Coimbra, Coimbra 3004-535, Portugal
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8
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Lomaka A, Tamm T. Linearization of moment tensor potentials for multicomponent systems with a preliminary assessment for short-range interaction energy in water dimer and trimer. J Chem Phys 2020; 152:164115. [DOI: 10.1063/5.0007473] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Andre Lomaka
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Tallinn, Estonia
| | - Toomas Tamm
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Tallinn, Estonia
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9
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Wang CH, Masunov AE, Allison TC, Chang S, Lim C, Jin Y, Vasu SS. Molecular Dynamics of Combustion Reactions in Supercritical Carbon Dioxide. 6. Computational Kinetics of Reactions between Hydrogen Atom and Oxygen Molecule H + O 2 ⇌ HO + O and H + O 2 ⇌ HO 2. J Phys Chem A 2019; 123:10772-10781. [PMID: 31820644 DOI: 10.1021/acs.jpca.9b08789] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Reactions of the hydrogen atom and the oxygen molecule are among the most important ones in the hydrogen and hydrocarbon oxidation mechanisms, including combustion in a supercritical CO2 (sCO2) environment, known as oxy-combustion or the Allam cycle. Development of these energy technologies requires understanding of chemical kinetics of H + O2 ⇌ HO + O and H + O2 ⇌ HO2 in high pressures and concentrations of CO2. Here, we combine quantum treatment of the reaction system by the transition state theory with classical molecular dynamics simulation and the multistate empirical valence bonding method to treat environmental effects. Potential of mean force in the sCO2 solvent at various temperatures 1000-2000 K and pressures 100-400 atm was obtained. The reaction rate for H + O2 ⇌ HO + O was found to be pressure-independent and described by the extended Arrhenius equation 4.23 × 10-7 T-0.73 exp(-21 855.2 cal/mol/RT) cm3/molecule/s, while the reaction rate H + O2 ⇌ HO2 is pressure-dependent and can be expressed as 5.22 × 10-2 T-2.86 exp(-7247.4 cal/mol/RT) cm3/molecule/s at 300 atm.
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Affiliation(s)
- Chun-Hung Wang
- NanoScience Technology Center , University of Central Florida , 12424 Research Parkway , Orlando , Florida 32826 , United States
| | - Artëm E Masunov
- NanoScience Technology Center , University of Central Florida , 12424 Research Parkway , Orlando , Florida 32826 , United States.,School of Modeling, Simulation, and Training , University of Central Florida , 3100 Technology Parkway , Orlando , Florida 32816 , United States.,Department of Chemistry , University of Central Florida , 4111 Libra Drive , Orlando , Florida 32816 , United States.,South Ural State University , Lenin pr. 76 , Chelyabinsk 454080 , Russia.,National Research Nuclear University MEPhI , Kashirskoye shosse 31 , Moscow 115409 , Russia
| | - Timothy C Allison
- Southwest Research Institute , San Antonio , Texas 78238 , United States
| | - Sungho Chang
- KEPCO Research Institute , Daejeon 34050 , Korea
| | - Chansun Lim
- Hanwha Power Systems , Seongnam , Gyeonggi 13488 , Korea
| | - Yuin Jin
- Hanwha Power Systems , Seongnam , Gyeonggi 13488 , Korea
| | - Subith S Vasu
- Center for Advanced Turbomachinery and Energy Research (CATER), Mechanical and Aerospace Engineering , University of Central Florida , Orlando , Florida 32816 , United States
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10
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Rocha CMR, Varandas AJC. A global CHIPR potential energy surface for ground-state C 3H and exploratory dynamics studies of reaction C 2 + CH → C 3 + H. Phys Chem Chem Phys 2019; 21:24406-24418. [PMID: 31663556 DOI: 10.1039/c9cp04890a] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A full-dimensional global potential-energy surface (PES) is first reported for ground-state doublet C3H using the combined-hyperbolic-inverse-power-representation (CHIPR) method and accurate ab initio energies extrapolated to the complete basis set limit. The PES is based on a many-body expansion-type development where the two-body and three-body energy terms are from our previously reported analytic potentials for C2H(2A') and C3(1A',3A'), while the effective four-body one is calibrated using an extension of the CHIPR formalism for tetratomics. The final form is shown to accurately reproduce all known stationary structures of the PES, some of which are unreported thus far, and their interconversion pathways. Moreover, it warrants by built-in construction the appropriate permutational symmetry and describes in a physically reasonable manner all long-range features and the correct asymptotic behavior at dissociation. Exploratory quasi-classical trajectory calculations for the reaction C2 + CH → C3 + H are also performed, yielding thermalized rate coefficients for temperatures up to 4000 K.
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Affiliation(s)
- C M R Rocha
- Department of Chemistry and Coimbra Chemistry Centre, University of Coimbra, 3004-535 Coimbra, Portugal.
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11
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Rocha CMR, Varandas AJC. Accurate CHIPR Potential Energy Surface for the Lowest Triplet State of C 3. J Phys Chem A 2019; 123:8154-8169. [PMID: 31184891 DOI: 10.1021/acs.jpca.9b03194] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report the first global ab initio-based potential energy surface (PES) for ground-state triplet C3(3A') based on accurate energies extrapolated to the complete basis set (CBS) limit, and using the combined-hyperbolic-inverse-power-representation method for the analytical modeling. By relying on a cost-effective CBS(D,T) protocol, we ensure that the final form reproduces all topographical features of the PES, including its cyclic-linear isomerization barrier, with CBS(5,6)-quality. To partially account for the incompleteness of the N-electron basis and other minor effects, the available accurate experimental data on the relevant diatomics were used to obtain direct-fit curves that replace the theoretical ones in the many-body expansion. Besides describing properly long-range interactions at all asymptotic channels and permutational symmetry by built-in construction, the PES reported here reproduces the proper exothermicities at dissociation regions as well as the spectroscopy of the diatomic fragments. Bound vibrational state calculations in both linear and cyclic isomers have also been carried out, unveiling a good match of the available data on C3(ã 3Πu), while assisting with IR band positions for C3(3A2') that may serve as a guide for its laboratory and astronomical detection.
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Affiliation(s)
- C M R Rocha
- Coimbra Chemistry Centre and Chemistry Department , University of Coimbra , 3004-535 Coimbra , Portugal
| | - A J C Varandas
- Coimbra Chemistry Centre and Chemistry Department , University of Coimbra , 3004-535 Coimbra , Portugal.,School of Physics and Physical Engineering , Qufu Normal University , Qufu 273165 , P. R. China
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12
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Rocha CMR, Li J, Varandas AJC. Difficulties and Virtues in Assessing the Potential Energy Surfaces of Carbon Clusters via DMBE Theory: Stationary Points of C κ (κ = 2-10) at the Focal Point. J Phys Chem A 2019; 123:3121-3130. [PMID: 30632758 DOI: 10.1021/acs.jpca.8b11632] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The previously reported potential energy surfaces (PESs) of ground-state singlet C3 and triplet C4 are here utilized as input for the construction of approximate cluster expansions for larger Cκ (κ = 5-10) species. Relying primarily on the double many-body expansion (DMBE) approach, global potentials are obtained by summing the total interaction energies of all atomic subclusters up to four-body terms. The notable capability of the final forms in predicting good estimates of the linear global minima and their thermochemical/structural properties may provide important insights into the structure-determining nature of the (2 + 3 + 4) terms. The main difficulties and virtues in assessing Cκ's via DMBE theory are analyzed and new prospects given for the construction of global reliable PESs for the target species.
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Affiliation(s)
- C M R Rocha
- Department of Chemistry and Coimbra Chemistry Centre , University of Coimbra 3004-535 Coimbra , Portugal
| | - Jing Li
- School of Physics and Physical Engineering , Qufu Normal University , Qufu 273165 , P.R. China
| | - A J C Varandas
- Department of Chemistry and Coimbra Chemistry Centre , University of Coimbra 3004-535 Coimbra , Portugal.,School of Physics and Physical Engineering , Qufu Normal University , Qufu 273165 , P.R. China
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13
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Affiliation(s)
- Jian-wei Cao
- Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Feng-yi Li
- Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wen-sha Xia
- Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wen-sheng Bian
- Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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14
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Xavier FGD, González MM, Varandas AJC. Global Potential Energy Surface for HO 2+ Using the CHIPR Method. J Phys Chem A 2019; 123:1613-1621. [PMID: 30707025 DOI: 10.1021/acs.jpca.8b12005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
An analytical potential energy function for the title ion based on the combined hyperbolic inverse power representation (CHIPR) method and its characteristics are discussed at length in the present work. The curves of two diatomic ions, O2+ and OH+, are also obtained within the same approach. The model PES so obtained exhibits extraordinary flexibility in describing with subchemical accuracy even the weak topological features near the higher energy regions. Thus, structural properties predicted by the model may help spectroscopists who want to compare their experimental values with the ones from theory. The relaxed PESs in various coordinates have been calculated by relaxing the O2 bond distance using the present model, thus throwing light on all the possible isomers and their interconversions. The latest estimates of IR frequencies for three vibrational modes have been compared with the computed frequencies using the present model, and the agreement seems encouraging.
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Affiliation(s)
- F George D Xavier
- Department of Chemistry , University of Coimbra , 3004-525 Coimbra , Portugal
| | - M Martínez González
- Department of Chemistry , University of Coimbra , 3004-525 Coimbra , Portugal.,Facultad de Química , Universidad de La Habana , calle San Lázaro sn. , 10400 La Habana , Cuba
| | - A J C Varandas
- Department of Chemistry , University of Coimbra , 3004-525 Coimbra , Portugal.,School of Physics and Physical Engineering , Qufu Normal University , 273165 Qufu , China
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15
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Ghosh S, Sharma R, Adhikari S, Varandas AJC. Fully coupled (J > 0) time-dependent wave-packet calculations using hyperspherical coordinates for the H + O2 reaction on the CHIPR potential energy surface. Phys Chem Chem Phys 2019; 21:20166-20176. [DOI: 10.1039/c9cp03171e] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
ICS calculation by time dependent wavepacket approach for H + O2 reaction using non-zero J values.
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Affiliation(s)
- Sandip Ghosh
- School of Chemical Sciences
- Indian Association for the Cultivation of Science
- Kolkata-700032
- India
| | - Rahul Sharma
- Department of Chemistry
- St. Xaviers' College
- Kolkata-700016
- India
| | - Satrajit Adhikari
- School of Chemical Sciences
- Indian Association for the Cultivation of Science
- Kolkata-700032
- India
| | - António J. C. Varandas
- School of Physics and Physical Engineering
- Qufu Normal University
- 273165 Qufu
- China
- Departamento de Química, and Centro de Química
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16
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Zuo JX, Hu XX, Xie DQ. Quantum Dynamics of Oxyhydrogen Complex-Forming Reactions for the HO2 and HO3 Systems. CHINESE J CHEM PHYS 2018. [DOI: 10.1063/1674-0068/31/cjcp1804060] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Jun-xiang Zuo
- Institute of Theoretical and Computational Chemistry, Key Laboratory of Mesoscopic Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China
| | - Xi-xi Hu
- Institute of Theoretical and Computational Chemistry, Key Laboratory of Mesoscopic Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China
| | - Dai-qian Xie
- Institute of Theoretical and Computational Chemistry, Key Laboratory of Mesoscopic Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China
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17
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Rocha CMR, Varandas AJC. Multiple conical intersections in small linear parameter Jahn-Teller systems: the DMBE potential energy surface of ground-state C 3 revisited. Phys Chem Chem Phys 2018; 20:10319-10331. [PMID: 29610812 DOI: 10.1039/c7cp06656b] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A new single-sheeted DMBE potential energy surface for ground-state C3 is reported. The novel analytical form accurately describes the three symmetry-equivalent C2v disjoint seams, in addition to the symmetry-required D3h one, over the entire configuration space. The present formalism warrants by built-in construction the confluence of the above crossings, and the rotation-in-plane of the C2v seams when the perimeter of the molecule fluctuates. Up to 1050 ab initio energies have been employed in the calibration procedure, of which 421 map the loci of intersection. The calculated energies have been scaled to account for the incompleteness of the basis set and truncation of the MRCI expansion, and fitted analytically with chemical accuracy. The novel form is shown to accurately mimic the region defined by the 4 conical intersections, while exhibiting similar attributes to the previously reported one [J. Chem. Phys., 2015, 143, 074302] at the regions of configuration space away from the crossing seams. Despite being mainly addressed to C3, the present approach should be applicable to adiabatic PESs of any X3 system experiencing similar topological attributes, in particular the small-linear-parameter Jahn-Teller molecules.
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Affiliation(s)
- C M R Rocha
- Departamento de Química, and Centro de Química, Universidade de Coimbra, 3004-535 Coimbra, Portugal.
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18
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Ghosh S, Sharma R, Adhikari S, Varandas AJC. 3D time-dependent wave-packet approach in hyperspherical coordinates for the H + O2 reaction on the CHIPR and DMBE IV potential energy surfaces. Phys Chem Chem Phys 2018; 20:478-488. [DOI: 10.1039/c7cp06254k] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
3D wavepacket quantum dynamics methodology ICS calculation of H + O2 reaction on the CHIPR and DMBE IV PESs by J-shifting scheme.
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Affiliation(s)
- Sandip Ghosh
- Department of Physical Chemistry
- Indian Association for the Cultivation of Science
- Kolkata-700032
- India
| | - Rahul Sharma
- Department of Chemistry
- St. Xaviers’ College
- Kolkata-700016
- India
| | - Satrajit Adhikari
- Department of Physical Chemistry
- Indian Association for the Cultivation of Science
- Kolkata-700032
- India
| | - António J. C. Varandas
- Departamento de Química
- and Centro de Química
- Universidade de Coimbra
- 3004-535 Coimbra
- Portugal
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19
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Teixidor MM, Varandas AJ. Quantum dynamics study of the X+O2 reactions on the CHIPR potential energy surface: X=Mu, H, D, T. Chem Phys Lett 2015. [DOI: 10.1016/j.cplett.2015.08.028] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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20
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Rocha CMR, Varandas AJC. Accurate ab initio-based double many-body expansion potential energy surface for the adiabatic ground-state of the C3 radical including combined Jahn-Teller plus pseudo-Jahn-Teller interactions. J Chem Phys 2015; 143:074302. [DOI: 10.1063/1.4928434] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Affiliation(s)
- C. M. R. Rocha
- Departamento de Química, and Centro de Química, Universidade de Coimbra, 3004-535 Coimbra, Portugal
| | - A. J. C. Varandas
- Departamento de Química, and Centro de Química, Universidade de Coimbra, 3004-535 Coimbra, Portugal
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21
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Teixidor MM, Varandas AJC. Quantum dynamics study on the CHIPR potential energy surface for the hydroperoxyl radical: the reactions O + OH⇋O2 + H. J Chem Phys 2015; 142:014309. [PMID: 25573563 DOI: 10.1063/1.4905292] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Quantum scattering calculations of the O((3)P)+OH((2)Π)⇌O2((3)Σg (-))+H((2)S) reactions are presented using the combined-hyperbolic-inverse-power-representation potential energy surface [A. J. C. Varandas, J. Chem. Phys. 138, 134117 (2013)], which employs a realistic, ab initio-based, description of both the valence and long-range interactions. The calculations have been performed with the ABC time-independent quantum reactive scattering computer program based on hyperspherical coordinates. The reactivity of both arrangements has been investigated, with particular attention paid to the effects of vibrational excitation. By using the J-shifting approximation, rate constants are also reported for both the title reactions.
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Affiliation(s)
- Marc Moix Teixidor
- Departamento de Química and Centro de Química, Universidade de Coimbra, 3004-535 Coimbra, Portugal
| | - António J C Varandas
- Departamento de Química and Centro de Química, Universidade de Coimbra, 3004-535 Coimbra, Portugal
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22
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Galvão BRL, Mota VC, Varandas AJC. Modeling cusps in adiabatic potential energy surfaces. J Phys Chem A 2015; 119:1415-21. [PMID: 25633429 DOI: 10.1021/jp512671q] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A method for modeling cusps on adiabatic potential energy surfaces without the need for any adiabatic-to-diabatic transformation is presented and shown to be successfully applied to the (2)A″ state of NO2. The more complicated case of a system with permutationally equivalent crossing seams is also examined and illustrated by considering the two first (2)A' states of the nitrogen trimer.
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Affiliation(s)
- B R L Galvão
- Departamento de Química, Centro Federal de Educação Tecnológica de Minas Gerais, CEFET-MG , Av. Amazonas 5253, 30421-169 Belo Horizonte, Minas Gerais, Brazil
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23
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Varandas AJC, Galvão BRL. Exploring the Utility of Many-Body Expansions: A Consistent Set of Accurate Potentials for the Lowest Quartet and Doublet States of the Azide Radical with Revisited Dynamics. J Phys Chem A 2014; 118:10127-33. [DOI: 10.1021/jp5087027] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- A. J. C. Varandas
- Departamento
de Quı́mica, Universidade de Coimbra, 3004-535 Coimbra, Portugal
| | - B. R. L. Galvão
- Departamento
de Quı́mica, Centro Federal de Educação Tecnológica de Minas Gerais, CEFET-MG, Av. Amazonas 5253, 30421-169 Belo Horizonte, Minas Gerais, Brazil
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24
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Li J, Varandas AJC. Accurate double many-body expansion potential energy surface for the 21A′ state of N2O. J Chem Phys 2014; 141:084307. [DOI: 10.1063/1.4893951] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Jing Li
- Departamento de Química, Universidade de Coimbra 3004-535 Coimbra, Portugal
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25
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Teixeira OBM, Mota VC, Garcia de la Vega JM, Varandas AJC. Single-Sheeted Double Many-Body Expansion Potential Energy Surface for Ground-State ClO2. J Phys Chem A 2014; 118:4851-62. [DOI: 10.1021/jp503744x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- O. B. M. Teixeira
- Departamento
de Química Física Aplicada, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - V. C. Mota
- Departamento
de Física, Universidade Federal do Espirito Santo, 29075-910 Vitória, Brazil
| | - J. M. Garcia de la Vega
- Departamento
de Química Física Aplicada, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - A. J. C. Varandas
- Departamento
de Física, Universidade Federal do Espirito Santo, 29075-910 Vitória, Brazil
- Centro de Química,
and Departamento de Química, Universidade de Coimbra, 3004-535 Coimbra, Portugal
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26
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Varandas AJC. Accurate Determination of the Reaction Course in HY2 ⇌ Y + YH (Y = O, S): Detailed Analysis of the Covalent- to Hydrogen-Bonding Transition. J Phys Chem A 2013; 117:7393-407. [DOI: 10.1021/jp401384d] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- A. J. C. Varandas
- Departamento
de Química, Universidade de Coimbra, 3004-535 Coimbra,
Portugal
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27
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Varandas AJC. Accurate combined-hyperbolic-inverse-power-representation of ab initio potential energy surface for the hydroperoxyl radical and dynamics study of O+OH reaction. J Chem Phys 2013; 138:134117. [DOI: 10.1063/1.4795826] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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