English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Currently, there is a growing interest in the development of a new hierarchyof methods based on the concept of seniority, which has been introduced quiterecently in quantum chemistry. Despite the enormous potential of these methods,the accurate description of both dynamical and static correlation effectswithin a single and in-principle-exact approach remains a challenge. In thiswork, we propose an alternative formulation of reduced density-matrixfunctional theory (RDMFT) where the (one-electron reduced) density matrix ismapped onto an ab initio seniority-zero wave function. In this theory, theexact natural orbitals and their occupancies are determined self-consistentlyfrom an effective seniority-zero calculation. The latter involves a universalhigher-seniority density matrix functional for which an adiabatic connection(AC) formula is derived and implemented under specific constraints that arerelated to the density matrix. The pronounced curvature of the (constrained) ACintegrand, which is numerically observed in prototypical hydrogen chains andthe Helium dimer, indicates that a description of higher-seniority correlationswithin second-order perturbation theory is inadequate in this context. Applyingmultiple linear interpolations along the AC or connecting second-orderperturbation theory to a full-seniority treatment via Pad\'{e} approximants arebetter strategies. Such information is expected to serve as a guide in thefuture design of higher-seniority density-matrix functional approximations.

physical review. a/physical review, a

Reduced density matrix functional theory from an ab initio  seniority-zero wave function: Exact and approximate formulations along  adiabatic connection paths