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🔬 ORCA Quantum Chemistry Software

ORCA is a flexible, efficient, and powerful quantum chemistry package used for DFT and post-HF computations.

🛠️ How to Install ORCA

To install ORCA:

  1. Download from ORCA Forum
  2. Extract and place the folder in your desired path
  3. Update your .bashrc or .zshrc with:
    export PATH=$PATH:/path/to/orca
  4. Test by running: orca input.inp > output.out

⚙️ ORCA Run Types

Single Point
Single Point

Calculates the electronic energy at a fixed geometry without any structure optimization.

Optimization
Geometry Optimization

Finds the lowest energy molecular geometry by adjusting atom positions iteratively.

Frequency
Frequency Calculation

Determines vibrational frequencies and thermodynamic properties of the molecule.

TD-DFT
TD-DFT

Time-Dependent DFT calculations for excited states, UV/Vis absorption spectra, and electronic transitions.

NEB
NEB Pathway

Calculates reaction paths using Nudged Elastic Band method between two endpoints.

CASSCF
CASSCF

Multiconfigurational electronic structure method for strongly correlated systems.