Multilayer Approach to the IP-EOM-DLPNO-CCSD Method: Theory, Implementation, and Application

2019 ◽  
Vol 15 (4) ◽  
pp. 2265-2277 ◽  
Author(s):  
Soumi Haldar ◽  
Christoph Riplinger ◽  
Baptiste Demoulin ◽  
Frank Neese ◽  
Robert Izsak ◽  
...  
Keyword(s):  
Ccsd Method

Accurate computations of 77Se NMR chemical shifts with the GIAO-CCSD method

1995 ◽  
Vol 241 (3) ◽  
pp. 248-252 ◽  
Author(s):  
Michael Bühl ◽  
Jürgen Gauss ◽  
John F. Stanton
Keyword(s):  
Chemical Shifts ◽  
Nmr Chemical Shifts ◽  
Ccsd Method ◽  
Accurate Computations

A systematic theoretical study of harmonic vibrational frequencies: The single and double excitation coupled cluster (CCSD) method

1988 ◽  
Vol 89 (1) ◽  
pp. 360-366 ◽  
Author(s):  
Brent H. Besler ◽  
Gustavo E. Scuseria ◽  
Andrew C. Scheiner ◽  
Henry F. Schaefer
Keyword(s):  
Theoretical Study ◽  
Vibrational Frequencies ◽  
Coupled Cluster ◽  
Double Excitation ◽  
Ccsd Method

scholarly journals CAP-EOM-CCSD Method with Smooth Voronoi CAP for Metastable Electronic States in Molecular Clusters

2020 ◽  
Author(s):  
James Gayvert ◽  
Ksenia Bravaya
Keyword(s):  
Molecular Species ◽  
Electronic States ◽  
Equation Of Motion ◽  
Molecular Clusters ◽  
Metastable States ◽  
Coupled Cluster ◽  
Vacuum Region ◽  
Practical Tool ◽  
Ccsd Method

The complex absorbing potential (CAP) approach offers a practical tool for characterization of energies and lifetimes of metastable electronic states, such as temporary anions and core ionized states. Here, we present an implementation of the smooth Voronoi CAP combined with equation-of-motion coupled cluster with single and double substitutions method for metastable states. The performance of the smooth Voronoi and a standard box CAPs is compared for different classes of systems: resonances in isolated molecules and in molecular clusters. The results of the benchmark calculations indicate that the choice of the CAP shape should be guided by the character of the metastable states. While Voronoi CAPs yield stable results in the case of a resonance localized on one molecule, their performance in the cases of states delocalized over two or more molecular species can deteriorate due to the CAP leaking into the vacuum region between the moieties. <br>

Massively parallel implementation of the multireference Brillouin–Wigner CCSD method

2011 ◽  
Vol 514 (4-6) ◽  
pp. 347-351 ◽  
Author(s):  
Jiří Brabec ◽  
Sriram Krishnamoorthy ◽  
Hubertus J.J. van Dam ◽  
Karol Kowalski ◽  
Jiří Pittner
Keyword(s):  
Parallel Implementation ◽  
Massively Parallel ◽  
Ccsd Method

Interatomic Coulombic decay in (n= 2–3) clusters using CAP/EOM-CCSD method

2013 ◽  
Vol 112 (5-6) ◽  
pp. 669-673 ◽  
Author(s):  
Aryya Ghosh ◽  
Sourav Pal ◽  
Nayana Vaval
Keyword(s):  
Ccsd Method

scholarly journals Performance of the DLPNO-CCSD and Recent DFT Methods in the Calculation of Isotropic and Dipolar Contributions to 14N Hyperfine Coupling Constants of Nitroxide Radicals

2021 ◽  
Author(s):  
Oleg Gromov
Keyword(s):  
Hyperfine Coupling ◽  
Coupling Constants ◽  
Density Functionals ◽  
Nitroxide Radicals ◽  
Dft Methods ◽  
Absolute Deviation ◽  
Anisotropic Hyperfine ◽  
Ccsd Method ◽  
Vibrational Correction ◽  
Good Agreement

Abstract In the present study, the performance of a set of density functionals: BP86, PBE, OLYP, BEEF, PBEpow, TPSS, SCAN, PBEGXPBE, M06L, MN15L, B3LYP, PBE0, mPW1PW, B97, BHandHLYP, mPW1PW, HSE06, B98, TPSS0, PBE1KCIS, SCAN0, M06, M06-2X, MN15, CAM-B3LYP, ωB97x, B2PLYP, and the B3LYP/N07D and PBE/N07D schemes in the calculation of the 14N anisotropic hyperfine coupling (HFC) constants of a set of 23 nitroxide radicals is evaluated. The results are compared with those obtained with the DLPNO-CCSD method and experimental HFC values. Harmonic contribution to the 14N HFC vibrational correction was calculated at the revPBE0/def2-TZVPP level and included in the evaluation. With the vibrational correction, the DLPNO-CCSD method yielded HFC values in good agreement with the experiment (MAD = 0.3 G for the dipole-dipole contribution and MAD = 0.8 G for the contact coupling contribution). The best DFT results are obtained using the M06 functional with mean absolute deviation (MAD) = 0.2 G for the dipole-dipole contribution and MAD = 0.7 G for the contact coupling contribution. In general, vibrational correction significantly improved most DFT functionals' performance but did not change its overall ranking.

scholarly journals CAP-EOM-CCSD Method with Smooth Voronoi CAP for Metastable Electronic States in Molecular Clusters

2020 ◽  
Author(s):  
James Gayvert ◽  
Ksenia Bravaya
Keyword(s):  
Molecular Species ◽  
Electronic States ◽  
Equation Of Motion ◽  
Molecular Clusters ◽  
Metastable States ◽  
Coupled Cluster ◽  
Vacuum Region ◽  
Practical Tool ◽  
Ccsd Method

The complex absorbing potential (CAP) approach offers a practical tool for characterization of energies and lifetimes of metastable electronic states, such as temporary anions and core ionized states. Here, we present an implementation of the smooth Voronoi CAP combined with equation-of-motion coupled cluster with single and double substitutions method for metastable states. The performance of the smooth Voronoi and a standard box CAPs is compared for different classes of systems: resonances in isolated molecules and in molecular clusters. The results of the benchmark calculations indicate that the choice of the CAP shape should be guided by the character of the metastable states. While Voronoi CAPs yield stable results in the case of a resonance localized on one molecule, their performance in the cases of states delocalized over two or more molecular species can deteriorate due to the CAP leaking into the vacuum region between the moieties. <br>

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