10.1. ORCA Structure

10.1.1. Program Components

The program system ORCA consists of several separate programs that call each other during a run. The following basic modules are included in this release (listed in alphabetical order):

orca

Main input+driver program

orca_ailft

Ab Initio Ligand Field Theory

orca_autoci

CI type program using the automated generation environment (ORCA-AGE)

orca_casscf

Main program for CASSCF driver

orca_casscfresp

CASSCF static linear response

orca_cclib

Precalculation of one particle coupling coefficients for ACCCI

orca_chelpg

Calculation of different kinds of ESP charges

orca_ciprep

Preparation of data for MRCI calculations (frozen core matrices and the like)

orca_cipsi

Iterative Configuration Expansion Configuration Interaction (ICE-CI)

orca_cis

Excited states via CIS and TD-DFT

orca_cisresp

CIS response calculation

orca_compound

General driver of the ORCA compound language

orca_crystalprep

Set up an embedding calculation from a crystal structure file

orca_eca

Auxiliary program for solving magnetic model Hamiltonians

orca_eda

Energy decomposition analysis module

orca_esd

Excited state dynamics program for calculating vibronic spectra, resonance Raman, …

orca_grad

General gradient module

orca_guess

Generation of an intial guess for SCF and CASSCF

orca_leanscf

Self consistent field program for HF and DFT

orca_lft

Ligand Field Theory

orca_loc

Calculation of localized molecular orbitals

orca_mcrpa

CASSCF linear response for excited states

orca_md

Molecular dynamics program

orca_mdci

Matrix driven correlation program: CI, CEPA, CPF, QCISD, CCSD(T)

orca_mm

Classical forcefield components

orca_mp2

MP2 program (conventional, direct and RI)

orca_mrci

MRCI and MRPT calculations (individually selecting)

orca_ndoint

Calculates semiempirical integrals and gradients

orca_nmrspectrum

Simulates NMR spectra from calculated NMR parameters

orca_numfreq

Numerical Hessian computation

orca_pc

Addition of point charge terms to the one-electron matrix

orca_plot

Generation of orbital and density plots

orca_pop

External program for population analysis on a given density

orca_prop

Calculation of molecular properties

orca_propint

Calculation of property integrals

orca_rel

(Quasi) Relativistic corrections

orca_rocis

Excited states via the ROCIS method

orca_scfgrad

Analytic derivatives of SCF energies (HF and DFT)

orca_scfresp

self consistent field response

orca_startup

Calculation of startup data before each single point

orca_vpot

Calculation of the electrostatic potential on a given molecular surface

orca_vpt2

VPT2 analysis