6533b852fe1ef96bd12aad29
RESEARCH PRODUCT
Analytic second derivatives for general coupled-cluster and configuration-interaction models.
Mihály KállayJürgen Gausssubject
Coupled clusterChemistryChemical shiftMathematical analysisC++ string handlingGeneral Physics and AstronomyPhysical and Theoretical ChemistryAtomic physicsConfiguration interactionWave functionEnergy (signal processing)ExcitationSecond derivativedescription
Analytic second derivatives of energy for general coupled-cluster (CC) and configuration-interaction (CI) methods have been implemented using string-based many-body algorithms. Wave functions truncated at an arbitrary excitation level are considered. The presented method is applied to the calculation of CC and CI harmonic frequencies and nuclear magnetic resonance chemical shifts up to the full CI level for some selected systems. The present benchmarks underline the importance of higher excitations in high-accuracy calculations.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2004-04-15 | The Journal of chemical physics |