Assessing MP2 frozen natural orbitals for ...
Document type :
Autre communication scientifique (congrès sans actes - poster - séminaire...)
Permalink :
Title :
Assessing MP2 frozen natural orbitals for relativistic electronic structure
Author(s) :
Yuan, Xiang [Orateur]
Physico-Chimie Moléculaire Théorique [PCMT]
Visscher, Lucas [Auteur]
Severo Pereira Gomes, Andre [Auteur]
Physico-Chimie Moléculaire Théorique [PCMT]
Physico-Chimie Moléculaire Théorique [PCMT]
Visscher, Lucas [Auteur]
Severo Pereira Gomes, Andre [Auteur]

Physico-Chimie Moléculaire Théorique [PCMT]
Conference title :
Workshop of the GDR quantum gases
City :
Lille
Country :
France
Start date of the conference :
2022-10-24
Publication date :
2022-10-24
HAL domain(s) :
Chimie/Chimie théorique et/ou physique
Physique [physics]/Physique [physics]/Chimie-Physique [physics.chem-ph]
Physique [physics]/Physique [physics]/Chimie-Physique [physics.chem-ph]
English abstract : [en]
The O(N<sup>6</sup>) computation cost is a bottleneck preventing performing Coupled-Cluster (CC) on large systems, particularly when employing 4- component based relativistic Hamiltonians, for which in practice one often ...
Show more >The O(N<sup>6</sup>) computation cost is a bottleneck preventing performing Coupled-Cluster (CC) on large systems, particularly when employing 4- component based relativistic Hamiltonians, for which in practice one often uses uncontracted basis set generating large virtual molecular orbitalspaces.<br>The canonical Hartree-Fock (HF) orbitals are not the most compact representation for post HF method. On other hand, using natural orbital is an efficient way to reduce the orbital space and maintains most of the accuracy. We therefore implemented the MP2 frozen natural orbital (FNO) method [1] in the Exacorr code [2], with the particularity that our implementation can generate both complex and quaternion FNOs, and also express these in AO basis. It also allows us to obtain CCSD natural orbitals on AO basis, which can be subsequently used in analysis. We have investigated the orbital truncation errors in both correlation energy and molecular properties including dipole, quadrupole moment, electric filed gradient, for hydrogen halides HX (X=F, Cl, Br, I, At, Ts), and parity violation for the H<sub>2</sub>X<sub>2</sub> (X= O, S, Se, Te, Po) molecules. We find that FNO indeed accelerates rapidly the correlation energy convergence. For properties, truncated FNO spaces seem to slightly outperform canonical HF orbitals, and to provide reliable estimates for the molecular properties obtained for complete virtual spaces [3].<b>Reference</b>[1] T. L. Barr, E. R. Davidson, Phys. Rev. A 1970, 1, 644; A. G. Taube, R. J. Bartlett, <i>J. Chem. Phys.</i> 2008, <b>128</b>, 164101<br>[2] J. V. Pototschnig, A. Papadopoulos, D. I. Lyakh, M. Repisky, L. Halbert, A. S. P. Gomes, H- JAa. Jensen, L. Visscher, <i>J. Chem. Theory. Comput.</i> 2021, <b>17</b>, 5509<br>[3] X. Yuan, L. Visscher, ASP. Gomes, <i>J. Chem. Phys.</i> 2022, arXiv:2202.01146<br>Show less >
Show more >The O(N<sup>6</sup>) computation cost is a bottleneck preventing performing Coupled-Cluster (CC) on large systems, particularly when employing 4- component based relativistic Hamiltonians, for which in practice one often uses uncontracted basis set generating large virtual molecular orbitalspaces.<br>The canonical Hartree-Fock (HF) orbitals are not the most compact representation for post HF method. On other hand, using natural orbital is an efficient way to reduce the orbital space and maintains most of the accuracy. We therefore implemented the MP2 frozen natural orbital (FNO) method [1] in the Exacorr code [2], with the particularity that our implementation can generate both complex and quaternion FNOs, and also express these in AO basis. It also allows us to obtain CCSD natural orbitals on AO basis, which can be subsequently used in analysis. We have investigated the orbital truncation errors in both correlation energy and molecular properties including dipole, quadrupole moment, electric filed gradient, for hydrogen halides HX (X=F, Cl, Br, I, At, Ts), and parity violation for the H<sub>2</sub>X<sub>2</sub> (X= O, S, Se, Te, Po) molecules. We find that FNO indeed accelerates rapidly the correlation energy convergence. For properties, truncated FNO spaces seem to slightly outperform canonical HF orbitals, and to provide reliable estimates for the molecular properties obtained for complete virtual spaces [3].<b>Reference</b>[1] T. L. Barr, E. R. Davidson, Phys. Rev. A 1970, 1, 644; A. G. Taube, R. J. Bartlett, <i>J. Chem. Phys.</i> 2008, <b>128</b>, 164101<br>[2] J. V. Pototschnig, A. Papadopoulos, D. I. Lyakh, M. Repisky, L. Halbert, A. S. P. Gomes, H- JAa. Jensen, L. Visscher, <i>J. Chem. Theory. Comput.</i> 2021, <b>17</b>, 5509<br>[3] X. Yuan, L. Visscher, ASP. Gomes, <i>J. Chem. Phys.</i> 2022, arXiv:2202.01146<br>Show less >
Language :
Anglais
Peer reviewed article :
Oui
Audience :
Nationale
Popular science :
Non
ANR Project :
Source :
Submission date :
2023-05-07T20:47:42Z