Molecular Dipole Moments within the Incremental Scheme Using the Domain-Specific Basis-Set Approach

Abstract

We present the first implementation of the fully automated incremental scheme for CCSD unrelaxed dipole moments using the domain-specific basis-set approach. Truncation parameters are varied, and the accuracy of the method is statistically analyzed for a test set of 20 molecules. The local approximations introduce small errors at second order and negligible ones at third order. For a third-order incremental CCSD expansion with a CC2 error correction, a cc-pVDZ/SV domain-specific basis set (tmain = 3.5 Bohr), and the truncation parameter f = 30 Bohr, we obtain a mean error of 0.00 mau (-0.20 mau) and a standard deviation of 1.95 mau (2.17 mau) for the total dipole moments (Cartesian components of the dipole vectors). By analyzing incremental CCSD energies, we demonstrate that the MP2 and CC2 error correction schemes are an exclusive correction for the domain-specific basis-set error. Our implementation of the incremental scheme provides fully automated computations of highly accurate dipole moments at reduced computational cost and is fully parallelized in terms of the calculation of the increments. Therefore, one can utilize the incremental scheme, on the same hardware, to extend the basis set in comparison to standard CCSD and thus obtain a better total accuracy.

More Stable Template Localization for an Incremental Focal-Point Approach—Implementation and Application to the Intramolecular Decomposition of Tris-perfluoro-tert-butoxyalane

“…Please note that this scheme corrects only for the domain-specific basis set error, as demonstrated previously …”

“…The method was successfully used for a broad class of chemical structures in the last years, including periodic systems − and molecules with closed-shell − and open-shell − as well as multireference character . Additionally the scheme was applied to calculate molecular properties, such as dipole moments, quadrupole moments, and polarizabilities. , …”

“…Please note that this scheme corrects only for the domainspecific basis set error, as demonstrated previously. 92 Template Localization. One critical step in the incremental scheme is the mapping of the orbitals in the domain-specific basis (B1) to those in the SV basis (B2).…”

Third-Order Many-Body Expansion of OSV-MP2 Wave Function for Low-Order Scaling Analytical Gradient Computation

“…Moreover, many structural and spectroscopic properties can be also cast as energy derivatives of the MBE eq with respect to a perturbation, This underlies very promising protocol for computing the properties of extended systems at correlated wave function level from MP2 to CC using term-by-term numerical or analytical differentiations of eq up to tractable orders. In recent years, successful applications have been highlighted in a number of ab initio problems involving electric-field derivatives for electric moments, , polarizabilities, , and vibrational spectra, − and nuclear gradients for geometry optimizations ,− and molecular dynamics (MD) simulations. − A tremendous variety of these MBE methods for both energies and properties feature the fragmentation schemes in which the subsystems are formed by properly and explicitly cutting macromolecules into overlapping or nonoverlapping atomic fragments , prior to post-HF. Alternatively interests also focus on designating the subsystems as tractable “ bodies ” by grouping orbital domains based on the starting HF wave function of the supersystem.…”

Third-order many-body expansion of OSV-MP2 wavefunction for low-order scaling analytical gradient computation

“…This underlies very promising protocol for computing the properties of extended systems at correlated wavefunction level from MP2 to CC using term-by-term numerical or analytical differentiations of eq 2 up to tractable orders. In recent years, successful applications have been highlighted in a number of ab-initio problems involving electric-field derivatives for electric moments, 67,68 polarizabilities 69,70 and vibrational spectra, [71][72][73] and nuclear gradients for geometry optimizations 55, [74][75][76][77] and molecular dynamics (MD) simulations. [78][79][80][81][82][83][84][85] A tremendous variety of these MBE methods for both energies and properties features the fragmentation schemes in which the subsystems are formed by properly and explicitly cutting macromolecule into overlapping or non-overlapping atomic fragments 86,87 prior to post-HF.…”