Quick Start

OpenQuantum is a command-line program driven by plain text input files. The section-based format is the only supported format:

  • Section-based: a task: header followed by MOLECULE, GEOMETRY, SCF, INT, DFT, SOLVATION, OPT, FREQ, MP2, CC, BASIS, SYMMETRY blocks terminated by END.
cargo run --release -p oquantum -- water_rhf.inp

Note: The binary is named oquantum. The -p oquantum is required because the workspace contains multiple crates.

Minimal RHF Energy on Water

task: RHF STO-3G

MOLECULE
  Charge        0
  Multiplicity  1
  Units         Angstrom
END

GEOMETRY
  O   0.000000   0.000000   0.117369
  H   0.756950   0.000000  -0.469476
  H  -0.756950   0.000000  -0.469476
END

Save this as water_rhf.inp and run:

cargo run --release -p oquantum -- water_rhf.inp

Anatomy of an Input File

Every input file consists of:

  1. task: line — Required. Sets the run type, method, and basis set. 
    task: RHF STO-3G
  2. MOLECULE section — Optional. Charge, multiplicity, coordinate units.
  3. GEOMETRY section — Required. Atom list with coordinates.
  4. Optional sections — BASIS, SCF, INT, DFT, SOLVATION, OPT, FREQ, MP2, CC, SYMMETRY — only include when you need non-default settings.

Section names are case-insensitive. Each section ends with END (or end) on its own line. Lines inside a section are key value pairs (whitespace-separated, comment lines start with # or !, blank lines are ignored).

Next Steps