Influence of the choice of projection manifolds in the CASPT2 implementation

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61388963%3A_____%2F17%3A00478552" target="_blank" >RIV/61388963:_____/17:00478552 - isvavai.cz</a>

Výsledek na webu

<a href="http://dx.doi.org/10.1080/00268976.2016.1271152" target="_blank" >http://dx.doi.org/10.1080/00268976.2016.1271152</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1080/00268976.2016.1271152" target="_blank" >10.1080/00268976.2016.1271152</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Influence of the choice of projection manifolds in the CASPT2 implementation

Popis výsledku v původním jazyce

The Complete Active Space Second-Order Perturbation Theory (CASPT2) is well-established as a high-accuracy electronic structure method. It was originally implemented in the early 1990s to an efficient computer code in the molcas program suite, and this implementation has been extensively used as a standard tool. Here, we report a comparison of it against two independent computer-aided implementations of the CASPT2 method, revealing that the CASPT2 energies provided by the original code of molcas (version 8 or earlier) are inconsistent with the predictions of the lately developed computer-aided implementations. It is shown that this error is associated with the projections of the first-order equation onto the fully internally contracted multireference bases which are partially inconsistent between the left- and right-hand sides. The degree of the errors is assessed by performing illustrative CASPT2 calculations. The errors in total CASPT2 energies are demonstrated to be negligible relative to chemical accuracy in many cases, while there is a difficult case where they may substantially alter chemical description. The incorporation of the consistent projections into molcas has been carried out, which is available in the version 8 sp1.

Název v anglickém jazyce

Influence of the choice of projection manifolds in the CASPT2 implementation

Popis výsledku anglicky

The Complete Active Space Second-Order Perturbation Theory (CASPT2) is well-established as a high-accuracy electronic structure method. It was originally implemented in the early 1990s to an efficient computer code in the molcas program suite, and this implementation has been extensively used as a standard tool. Here, we report a comparison of it against two independent computer-aided implementations of the CASPT2 method, revealing that the CASPT2 energies provided by the original code of molcas (version 8 or earlier) are inconsistent with the predictions of the lately developed computer-aided implementations. It is shown that this error is associated with the projections of the first-order equation onto the fully internally contracted multireference bases which are partially inconsistent between the left- and right-hand sides. The degree of the errors is assessed by performing illustrative CASPT2 calculations. The errors in total CASPT2 energies are demonstrated to be negligible relative to chemical accuracy in many cases, while there is a difficult case where they may substantially alter chemical description. The incorporation of the consistent projections into molcas has been carried out, which is available in the version 8 sp1.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10403 - Physical chemistry

Projekt

<a href="/cs/project/GA15-19143S" target="_blank" >GA15-19143S: Singletové štěpení</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2017

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Molecular Physics

ISSN

0026-8976

e-ISSN

—

Svazek periodika

115

Číslo periodika v rámci svazku

17/18

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

9

Strana od-do

2077-2085

Kód UT WoS článku

000408727700010

EID výsledku v databázi Scopus

2-s2.0-85007311372