# The ORCA program system

@article{Neese2012TheOP, title={The ORCA program system}, author={Frank Neese}, journal={Wiley Interdisciplinary Reviews: Computational Molecular Science}, year={2012}, volume={2} }

ORCA is a general‐purpose quantum chemistry program package that features virtually all modern electronic structure methods (density functional theory, many‐body perturbation and coupled cluster theories, and multireference and semiempirical methods). It is designed with the aim of generality, extendibility, efficiency, and user friendliness. Its main field of application is larger molecules, transition metal complexes, and their spectroscopic properties. ORCA uses standard Gaussian basis… Expand

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#### References

SHOWING 1-10 OF 37 REFERENCES

A spectroscopy oriented configuration interaction procedure

- Chemistry
- 2003

A multireference configuration interaction (MR-CI) based method (Spectroscopy ORiented CI, SORCI) is proposed to calculate energy differences between several electronic states of possibly different… Expand

Double-hybrid density functional theory for excited electronic states of molecules.

- Medicine, Chemistry
- The Journal of chemical physics
- 2007

Compared to conventional HF-based CIS(D), the method is more robust in electronically complex situations due to the implicit account of static correlation effects by the GGA parts and the (D) correction often works in the right direction. Expand

Assessment of Orbital-Optimized, Spin-Component Scaled Second-Order Many-Body Perturbation Theory for Thermochemistry and Kinetics.

- Physics, Medicine
- Journal of chemical theory and computation
- 2009

The numerical results show that OO-SCS-MP2 is a major improvement in electronically complicated situations, such as represented by radicals or by transition states where spin contamination often greatly deteriorates the quality of the conventional MP2 and SCS- MP2 methods. Expand

Efficient and accurate local approximations to coupled-electron pair approaches: An attempt to revive the pair natural orbital method.

- Chemistry, Medicine
- The Journal of chemical physics
- 2009

An efficient production level implementation of the closed shell CEPA and CPF methods is reported that can be applied to medium sized molecules and has essentially the same accuracy as parent CEPA (CPF) methods for thermochemistry, kinetics, weak interactions, and potential energy surfaces but is up to 500 times faster. Expand

Time-dependent density functional calculations of ligand K-edge X-ray absorption spectra

- Chemistry
- 2008

Abstract The Cl K-edge spectra of a series of metal tetrachloride complexes have been simulated using a simple TD-DFT based protocol. The influence of the chosen density functional, relativistics,… Expand

Advanced aspects of ab initio theoretical optical spectroscopy of transition metal complexes: Multiplets, spin-orbit coupling and resonance Raman intensities

- Chemistry
- 2007

Abstract In this review some advanced aspects of the theoretical methods for the calculation of transition metal optical spectra with ab initio methods are discussed. Density functional theory (DFT)… Expand

A Local Pair Natural Orbital Coupled Cluster Study of Rh Catalyzed Asymmetric Olefin Hydrogenation.

- Chemistry, Medicine
- Journal of chemical theory and computation
- 2010

The recently developed local pair natural orbital coupled cluster theory with single and double excitations (LPNO-CCSD) was used to study the rhodium-catalyzed asymmetric hydrogenation of two… Expand

Efficient and accurate approximations to the local coupled cluster singles doubles method using a truncated pair natural orbital basis.

- Chemistry, Medicine
- The Journal of chemical physics
- 2009

It is shown that for medium sized molecules the total wall clock time required to complete the LPNO-CCSD calculations is only two to four times that of the preceding self-consistent field (SCF) and these methods are highly suitable for large-scale computational chemistry applications. Expand

A comparative study of single reference correlation methods of the coupled-pair type

- Chemistry
- 2008

Abstract Several variants of coupled electron pair type approximations are compared with respect to their accuracy in the prediction of bond distances, harmonic vibrational frequencies and anharmonic… Expand

Geometries of Third-Row Transition-Metal Complexes from Density-Functional Theory.

- Medicine
- Journal of chemical theory and computation
- 2008

A set of 41 metal-ligand bond distances in 25 third-row transition-metal complexes, for which precise structural data are known in the gas phase, is used to assess optimized and zero-point averaged… Expand