1
|
Kędziorski A, Patrick Zobel J, Krośnicki M, Koperski J. Rydberg states of ZnAr complex. Mol Phys 2022. [DOI: 10.1080/00268976.2022.2073282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Andrzej Kędziorski
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Toruń, Toruń, Poland
| | - J. Patrick Zobel
- Institute of Theoretical Chemistry, University of Vienna, Vienna, Austria
| | - Marek Krośnicki
- Institute of Theoretical Physics and Astrophysics, Faculty of Mathematics, Physics and Informatics, University of Gdansk, Gdańsk, Poland
| | - Jarosław Koperski
- Smoluchowski Institute of Physics, Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, Kraków, Poland
| |
Collapse
|
2
|
Kodrycka M, Patkowski K. Efficient Density-Fitted Explicitly Correlated Dispersion and Exchange Dispersion Energies. J Chem Theory Comput 2021; 17:1435-1456. [PMID: 33606539 DOI: 10.1021/acs.jctc.0c01158] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The leading-order dispersion and exchange-dispersion terms in symmetry-adapted perturbation theory (SAPT), Edisp(20) and Eexch-disp(20), suffer from slow convergence to the complete basis set limit. To alleviate this problem, explicitly correlated variants of these corrections, Edisp(20)-F12 and Eexch-disp(20)-F12, have been proposed recently. However, the original formalism (M., Kodrycka , J. Chem. Theory Comput. 2019, 15, 5965-5986), while highly successful in terms of improving convergence, was not competitive to conventional orbital-based SAPT in terms of computational efficiency due to the need to manipulate several kinds of two-electron integrals. In this work, we eliminate this need by decomposing all types of two-electron integrals using robust density fitting. We demonstrate that the error of the density fitting approximation is negligible when standard auxiliary bases such as aug-cc-pVXZ/MP2FIT are employed. The new implementation allowed us to study all complexes in the A24 database in basis sets up to aug-cc-pV5Z, and the Edisp(20)-F12 and Eexch-disp(20)-F12 values exhibit vastly improved basis set convergence over their conventional counterparts. The well-converged Edisp(20)-F12 and Eexch-disp(20)-F12 numbers can be substituted for conventional Edisp(20) and Eexch-disp(20) ones in a calculation of the total SAPT interaction energy at any level (SAPT0, SAPT2+3, ...). We show that the addition of F12 terms does not improve the accuracy of low-level SAPT treatments. However, when the theory errors are minimized in high-level SAPT approaches such as SAPT2+3(CCD)δMP2, the reduction of basis set incompleteness errors thanks to the F12 treatment substantially improves the accuracy of small-basis calculations.
Collapse
Affiliation(s)
- Monika Kodrycka
- Department of Chemistry and Biochemistry, Auburn University, Auburn, Alabama 36849, United States
| | - Konrad Patkowski
- Department of Chemistry and Biochemistry, Auburn University, Auburn, Alabama 36849, United States
| |
Collapse
|
3
|
Computational Investigations of Dispersion Interactions between Small Molecules and Graphene-like Flakes. J Phys Chem A 2020; 124:9552-9561. [PMID: 33166136 DOI: 10.1021/acs.jpca.0c06595] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We investigate dispersion interactions in a selection of atomic, molecular, and molecule-surface systems, comparing high-level correlated methods with empirically corrected density functional theory (DFT). We assess the efficacy of functionals commonly used for surface-based calculations, with and without the D3 correction of Grimme. We find that the inclusion of the correction is essential to get meaningful results, but there is otherwise little to distinguish between the functionals. We also present coupled-cluster quality interaction curves for H2, NO2, H2O, and Ar interacting with large carbon flakes, acting as models for graphene surfaces, using novel absolutely localized molecular orbital based methods. These calculations demonstrate that the problems with empirically corrected DFT when investigating dispersion appear to compound as the system size increases, with important implications for future computational studies of molecule-surface interactions.
Collapse
|
4
|
Kruse H, Szabla R, Šponer J. Surprisingly broad applicability of the cc-pVnZ-F12 basis set for ground and excited states. J Chem Phys 2020; 152:214104. [PMID: 32505162 DOI: 10.1063/5.0006871] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Excellent convergence properties for the (aug-)cc-pVnZ-F12 basis set family, purpose-made for explicitly correlated calculations, are demonstrated with conventional wave function methods and Kohn-Sham density functional theory for various ground and excited-state calculations. Among the ground-state properties studied are dipole moments, covalent bond lengths, and interaction and reaction energies. For excited states, we looked at vertical excitation energies, UV absorption, and excited-state absorption spectra. Convergence is compared against the basis sets cc-pVnZ, def2-nVD, aug-pcseg-n, and nZaPa-NR. It is established that the cc-pVnZ-F12 family consistently yields results of n + 1 quality and better. Especially, the cc-pVDZ-F12 basis set is found to be a basis set of good cost vs performance trade-off.
Collapse
Affiliation(s)
- Holger Kruse
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 61265 Brno, Czech Republic
| | - Rafał Szabla
- EaStCHEM, School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, United Kingdom
| | - Jiří Šponer
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 61265 Brno, Czech Republic
| |
Collapse
|
5
|
Patkowski K. Recent developments in symmetry‐adapted perturbation theory. WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE 2019. [DOI: 10.1002/wcms.1452] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Konrad Patkowski
- Department of Chemistry and Biochemistry Auburn University Auburn Alabama
| |
Collapse
|
6
|
Kodrycka M, Holzer C, Klopper W, Patkowski K. Explicitly Correlated Dispersion and Exchange Dispersion Energies in Symmetry-Adapted Perturbation Theory. J Chem Theory Comput 2019; 15:5965-5986. [PMID: 31503481 DOI: 10.1021/acs.jctc.9b00547] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The individual interaction energy terms in symmetry-adapted perturbation theory (SAPT) not only have different physical interpretations but also converge to their complete basis set (CBS) limit values at quite different rates. Dispersion energy is notoriously the slowest converging interaction energy contribution, and exchange dispersion energy, while smaller in absolute value, converges just as poorly in relative terms. To speed up the basis set convergence of the lowest-order SAPT dispersion and exchange dispersion energies, we borrow the techniques from explicitly correlated (F12) electronic structure theory and develop practical expressions for the closed-shell Edisp(20)-F12 and Eexch-disp(20)-F12 contributions. While the latter term has been derived and implemented for the first time, the former correction was recently proposed by Przybytek [ J. Chem. Theory Comput. 2018 , 14 , 5105 - 5117 ] using an Ansatz with a full optimization of the explicitly correlated amplitudes. In addition to reimplementing the fully optimized variant of Edisp(20)-F12, we propose three approximate Ansätze that substantially improve the scaling of the method and at the same time avoid the numerical instabilities of the unrestricted optimization. The performance of all four resulting flavors of Edisp(20)-F12 and Eexch-disp(20)-F12 is first tested on helium, neon, argon, water, and methane dimers, with orbital and auxiliary basis sets up to aug-cc-pV5Z and aug-cc-pV5Z-RI, respectively. The double- and triple-ζ basis set calculations are then extended to the entire A24 database of noncovalent interaction energies and compared with CBS estimates for Edisp(20) and Eexch-disp(20) computed using conventional SAPT with basis sets up to aug-cc-pV6Z with midbond functions. It is shown that the F12 treatment is highly successful in improving the basis set convergence of the SAPT terms, with the F12 calculations in an X-tuple ζ basis about as accurate as conventional calculations in bases with cardinal numbers (X + 2) for Edisp(20) and either (X + 1) or (X + 2) for Eexch-disp(20). While the full amplitude optimization affords the highest accuracy for both corrections, the much simpler and numerically stable optimized diagonal Ansatz is a very close second. We have also tested the performance of the simple F12 correction based on the second-order Møller-Plesset perturbation theory, SAPT-F12(MP2) [ Frey , J. A. ; Chem. Rev. 2016 , 116 , 5614 - 5641 ] and observed that it is also quite successful in speeding up the basis set convergence of conventional Edisp(20) + Eexch-disp(20), albeit with some outliers.
Collapse
Affiliation(s)
- Monika Kodrycka
- Department of Chemistry and Biochemistry , Auburn University , Auburn , Alabama 36849 , United States
| | - Christof Holzer
- Theoretical Chemistry Group, Institute of Physical Chemistry , Karlsruhe Institute of Technology (KIT) , KIT Campus South , P.O. Box 6980, D-76049 Karlsruhe , Germany
| | - Wim Klopper
- Theoretical Chemistry Group, Institute of Physical Chemistry , Karlsruhe Institute of Technology (KIT) , KIT Campus South , P.O. Box 6980, D-76049 Karlsruhe , Germany
| | - Konrad Patkowski
- Department of Chemistry and Biochemistry , Auburn University , Auburn , Alabama 36849 , United States
| |
Collapse
|
7
|
Kodrycka M, Patkowski K. Platinum, gold, and silver standards of intermolecular interaction energy calculations. J Chem Phys 2019; 151:070901. [DOI: 10.1063/1.5116151] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Monika Kodrycka
- Department of Chemistry and Biochemistry, Auburn University, Auburn, Alabama 36849, USA
| | - Konrad Patkowski
- Department of Chemistry and Biochemistry, Auburn University, Auburn, Alabama 36849, USA
| |
Collapse
|
8
|
Rutskoy BV, Bezrukov DS. Ab Initio Description of the Structure and Interaction Energy of Perhalomethane Dimers. RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY A 2019. [DOI: 10.1134/s0036024419080259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
9
|
Hellmann R. Thermophysical Properties of Gaseous H2S–N2 Mixtures from First-Principles Calculations. ACTA ACUST UNITED AC 2018. [DOI: 10.1515/zpch-2018-1250] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
The cross second virial coefficient and three dilute gas transport properties (shear viscosity, thermal conductivity, and binary diffusion coefficient) of mixtures of hydrogen sulfide (H2S) and nitrogen (N2) were determined with high accuracy at temperatures up to 1200 K using statistical thermodynamics and the kinetic theory of molecular gases, respectively. The required intermolecular potential energy surface (PES) for the H2S–N2 interaction is presented in this work, while the H2S–H2S and N2–N2 PESs were reported previously. All three PESs are based on high-level quantum-chemical ab initio (i.e. first-principles) calculations. There is only very limited experimental information available on the second virial coefficients of H2S–N2 mixtures, and there appear to be no experimental data at all for the transport properties. Thus, the present predictions constitute a substantial increase in our knowledge of the thermophysical properties of this system, which are of practical relevance for modeling sour natural gas.
Collapse
Affiliation(s)
- Robert Hellmann
- Institut für Chemie, Universität Rostock , Albert-Einstein-Str. 3a , 18059 Rostock , Germany
| |
Collapse
|
10
|
Crusius JP, Hellmann R, Castro-Palacio JC, Vesovic V. Ab initio intermolecular potential energy surface for the CO2—N2 system and related thermophysical properties. J Chem Phys 2018; 148:214306. [DOI: 10.1063/1.5034347] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Affiliation(s)
- Johann-Philipp Crusius
- Department of Earth Science and Engineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - Robert Hellmann
- Institut für Chemie, Universität Rostock, 18059 Rostock, Germany
| | | | - Velisa Vesovic
- Department of Earth Science and Engineering, Imperial College London, London SW7 2AZ, United Kingdom
| |
Collapse
|
11
|
Dutta NN, Patkowski K. Improving “Silver-Standard” Benchmark Interaction Energies with Bond Functions. J Chem Theory Comput 2018; 14:3053-3070. [DOI: 10.1021/acs.jctc.8b00204] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Narendra Nath Dutta
- Department of Chemistry and Biochemistry, Auburn University, Auburn, Alabama 36849, United States
| | - Konrad Patkowski
- Department of Chemistry and Biochemistry, Auburn University, Auburn, Alabama 36849, United States
| |
Collapse
|
12
|
Affiliation(s)
- Robert A. Shaw
- Department of Chemistry, University of Sheffield, Sheffield, UK
| | - J. Grant Hill
- Department of Chemistry, University of Sheffield, Sheffield, UK
| |
Collapse
|
13
|
Rivera-Arrieta HI, Turney JM, Schaefer HF. Structural Distortions Accompanying Noncovalent Interactions: Methane–Water, the Simplest C–H Hydrogen Bond. J Chem Theory Comput 2017; 13:1478-1485. [DOI: 10.1021/acs.jctc.6b01008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Herzain I. Rivera-Arrieta
- Instituto
de Física, Universidad Nacional Autónoma de México, Ciudad de México 04510, México
- Center
for Computational Quantum Chemistry, Department of Chemistry, The University of Georgia, Athens, Georgia 30602-2556, United States
| | - Justin M. Turney
- Center
for Computational Quantum Chemistry, Department of Chemistry, The University of Georgia, Athens, Georgia 30602-2556, United States
| | - Henry F. Schaefer
- Center
for Computational Quantum Chemistry, Department of Chemistry, The University of Georgia, Athens, Georgia 30602-2556, United States
| |
Collapse
|
14
|
Sirianni DA, Burns LA, Sherrill CD. Comparison of Explicitly Correlated Methods for Computing High-Accuracy Benchmark Energies for Noncovalent Interactions. J Chem Theory Comput 2016; 13:86-99. [DOI: 10.1021/acs.jctc.6b00797] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Dominic A. Sirianni
- Center for Computational
Molecular Science and Technology, School of Chemistry and Biochemistry,
School of Computational Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
| | - Lori A. Burns
- Center for Computational
Molecular Science and Technology, School of Chemistry and Biochemistry,
School of Computational Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
| | - C. David Sherrill
- Center for Computational
Molecular Science and Technology, School of Chemistry and Biochemistry,
School of Computational Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
| |
Collapse
|
15
|
Rasmussen TH, Wang YM, Kjærgaard T, Kristensen K. The explicitly correlated same number of optimized parameters (SNOOP-F12) scheme for calculating intermolecular interaction energies. J Chem Phys 2016; 144:204102. [DOI: 10.1063/1.4950846] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Troels Hels Rasmussen
- Department of Chemistry, qLEAP Center for Theoretical Chemistry, Aarhus University, Langelandsgade 140, DK-8000 Aarhus C, Denmark
| | - Yang Min Wang
- Department of Chemistry, qLEAP Center for Theoretical Chemistry, Aarhus University, Langelandsgade 140, DK-8000 Aarhus C, Denmark
| | - Thomas Kjærgaard
- Department of Chemistry, qLEAP Center for Theoretical Chemistry, Aarhus University, Langelandsgade 140, DK-8000 Aarhus C, Denmark
| | - Kasper Kristensen
- Department of Chemistry, qLEAP Center for Theoretical Chemistry, Aarhus University, Langelandsgade 140, DK-8000 Aarhus C, Denmark
| |
Collapse
|
16
|
Shirkov L, Makarewicz J. Does DFT-SAPT method provide spectroscopic accuracy? J Chem Phys 2015; 142:064102. [DOI: 10.1063/1.4907204] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
|
17
|
Dagdigian PJ, Alexander MH. Transport Properties for Systems with Deep Potential Wells: H + O2. J Phys Chem A 2014; 118:11935-42. [DOI: 10.1021/jp505769h] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Paul J. Dagdigian
- Department
of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218-2685, United States
| | - Millard H. Alexander
- Department of Chemistry and Biochemistry and Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742-2021, United States
| |
Collapse
|
18
|
Smith DGA, Jankowski P, Slawik M, Witek HA, Patkowski K. Basis Set Convergence of the Post-CCSD(T) Contribution to Noncovalent Interaction Energies. J Chem Theory Comput 2014; 10:3140-50. [DOI: 10.1021/ct500347q] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Daniel G. A. Smith
- Department of Chemistry and
Biochemistry, Auburn University, Auburn, Alabama 36849, United States
| | - Piotr Jankowski
- Department
of Quantum Chemistry,
Faculty of Chemistry, Nicolaus Copernicus University, Gagarina
7, 87-100 Toruń, Poland
| | - Michał Slawik
- Department of Applied Chemistry
and Institute of Molecular Science, National Chiao Tung University, 1001 Ta-Hsueh Road, Hsinchu 30010, Taiwan
| | - Henryk A. Witek
- Department of Applied Chemistry
and Institute of Molecular Science, National Chiao Tung University, 1001 Ta-Hsueh Road, Hsinchu 30010, Taiwan
| | - Konrad Patkowski
- Department of Chemistry and
Biochemistry, Auburn University, Auburn, Alabama 36849, United States
| |
Collapse
|
19
|
Smith DGA, Patkowski K, Trinh D, Balakrishnan N, Lee TG, Forrey RC, Yang BH, Stancil PC. Highly Correlated Electronic Structure Calculations of the He–C3 van der Waals Complex and Collision-Induced Rotational Transitions of C3. J Phys Chem A 2014; 118:6351-60. [DOI: 10.1021/jp412048w] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Daniel G. A. Smith
- Department
of Chemistry and Biochemistry, Auburn University, 179 Chemistry Building, Auburn, Alabama 36849, United States
| | - Konrad Patkowski
- Department
of Chemistry and Biochemistry, Auburn University, 179 Chemistry Building, Auburn, Alabama 36849, United States
| | - Duy Trinh
- Department
of Chemistry, University of Nevada Las Vegas, 4505 South Maryland Parkway, Las Vegas, Nevada 89154, United States
| | - N. Balakrishnan
- Department
of Chemistry, University of Nevada Las Vegas, 4505 South Maryland Parkway, Las Vegas, Nevada 89154, United States
| | - Teck-Ghee Lee
- Department
of Physics, Auburn University, 206 Allison Laboratory, Auburn, Alabama 36849, United States
| | - Robert C. Forrey
- Department
of Physics, Penn State University, Berks Campus, 214 Luerssen
Building, Reading, Pennsylvania 19610, United States
| | - B. H. Yang
- Department
of Physics and Astronomy and Center for Simulational Physics, University of Georgia, Athens, Georgia 30602, United States
| | - P. C. Stancil
- Department
of Physics and Astronomy and Center for Simulational Physics, University of Georgia, Athens, Georgia 30602, United States
| |
Collapse
|
20
|
Dagdigian PJ, Alexander MH. Exact quantum scattering calculations of transport properties for the H2O–H system. J Chem Phys 2013; 139:194309. [DOI: 10.1063/1.4829681] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
21
|
Bakr BW, Smith DGA, Patkowski K. Highly accurate potential energy surface for the He–H2 dimer. J Chem Phys 2013; 139:144305. [DOI: 10.1063/1.4824299] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
22
|
Pacifici L, Verdicchio M, Lago NF, Lombardi A, Costantini A. A high-level ab initio study of the N2 + N2 reaction channel. J Comput Chem 2013; 34:2668-76. [PMID: 24037708 DOI: 10.1002/jcc.23415] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Revised: 07/26/2013] [Accepted: 07/27/2013] [Indexed: 11/08/2022]
Abstract
A new six-dimensional (6D) global potential energy surface (PES) is proposed for the full range description of the interaction of the N2(1Σg+)+N2(1Σg+) system governing collisional processes, including N atom exchange. The related potential energy values were determined using high-level ab initio methods. The calculations were performed at a coupled-cluster with single and double and perturbative triple excitations level of theory in order to have a first full range picture of the PES. Subsequently, in order to accurately describe the stretching of the bonds of the two interacting N2 molecules by releasing the constraints of being considered as rigid rotors, for the same molecular geometries higher level of theory multi reference calculations were performed. Out of the calculated values a 6D 4-atoms global PES was produced for use in dynamical calculations. The ab initio calculations were made possible by the combined use of High Throughput Computing and High Performance Computing techniques within the frame of a computing grid empowered molecular simulator.
Collapse
Affiliation(s)
- Leonardo Pacifici
- Department of Chemistry, University of Perugia, via Elce di Sotto, 8, Perugia, 06123, Italy
| | | | | | | | | |
Collapse
|