Issue 9, 2019

Symmetric dissociation of the water molecule with truncation energy error. A benchmark study

Abstract

We use selected configuration interaction with truncation energy error (SCI-TEE) and CI by parts (CIBP) to study the symmetric dissociation of the water molecule with Roos' triple-ζ double polarization basis set and with the Dunning cc-pVTZ basis. The calculations comprise CISDTQ (CI-4x) through CI-8x for H2O at its equilibrium geometry (Req) and up to fifteen times Req. With the Dunning basis our SCI-TEE-8x energies differ from full CI by less than 0.01 mHartree (0.006 kcal mol−1) at all O–H distances, representing the best upper bounds for this system outside Req. We compare our results with those of other relevant ab initio methods finding good agreement with recent DMRG calculations. The non-parallelity error (NPE) for SCI-TEE-6x remains stable below 0.1 mHartree when moving from the Roos to the Dunning orbitals. For the present system, CBS energy errors at the experimental equilibrium geometry and at dissociation can accurately be evaluated as the difference between non-relativistic total electronic energies taken from the literature, and our SCI-TEE-8x energies obtained with Dunning's or Roos' orbitals. In both cases, the difference between CBS energy errors at the equilibrium geometry and dissociation is not smaller than 10 mH, showing that chemically accurate NPE values do not guarantee a chemically accurate potential energy surface.

Graphical abstract: Symmetric dissociation of the water molecule with truncation energy error. A benchmark study

Supplementary files

Article information

Article type
Paper
Submitted
26 Okt 2018
Accepted
25 Jan 2019
First published
06 Feb 2019

Phys. Chem. Chem. Phys., 2019,21, 4953-4964

Symmetric dissociation of the water molecule with truncation energy error. A benchmark study

C. X. Almora-Díaz, A. Ramírez-Solís and C. F. Bunge, Phys. Chem. Chem. Phys., 2019, 21, 4953 DOI: 10.1039/C8CP06180G

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements