How openmopac/mopac works
MOPAC is a semiempirical quantum-chemistry program for molecular and materials calculations. The principal workflow reads a molecular system from input, performs an electronic-structure calculation, optionally relaxes geometry or computes vibrational properties, and emits results. It also exposes a diskless API for selected calculations and for running conventional input files; API state can be reused between calculations. The map reflects documented capabilities and the source tree’s module boundaries; implementation excerpts were limited to the public API header and partial build configuration, so detailed internal call wiring is not asserted.
Main entry points: properties Physical properties · mopac.h C API · SCF MOPAC SCF · integrals Integrals and matrices
Components 20
Execution interfaces
- Command-line program
src/interface - C API
include/mopac.h - Input processing
src/input
Electronic structure
- Chemical systems
src/chemistry - Semiempirical models
src/models - Model parameters
src/PARAM - Integrals and matrices
src/integrals - MOPAC SCF
src/SCF - MOZYME SCF
src/MOZYME - INDO method
src/INDO
Calculation stages
- Geometry processing
src/geometry - Geometry optimization
src/optimization - Forces and gradients
src/forces - Reaction calculations
src/reactions - Solvation models
src/solvation - Energy corrections
src/corrections
Results and properties
- Physical properties
src/properties - Result output
src/output
Scientific resources
Other components
- User or client
Connections 25
- User or client → Command-line program: runs calculation
- User or client → C API: calls API
- Command-line program → Input processing: processes input
- C API → Input processing: runs input file
- C API → MOPAC SCF: requests SCF
- C API → MOZYME SCF: requests MOZYME
- C API → Geometry optimization: requests relaxation
- C API → Physical properties: requests vibrations
- Input processing → Geometry processing: supplies system
- Geometry processing → Chemical systems: defines system
- Semiempirical models → Model parameters: uses parameters
- Chemical systems → Integrals and matrices: provides structure
- Semiempirical models → Integrals and matrices: selects model
- Integrals and matrices → MOPAC SCF: provides integrals
- Integrals and matrices → MOZYME SCF: provides integrals
- MOPAC SCF → INDO method: supports method
- MOPAC SCF → Forces and gradients: calculates gradients
- MOPAC SCF → Physical properties: produces properties
- MOZYME SCF → Physical properties: produces properties
- Geometry optimization → Forces and gradients: uses gradients
- Reaction calculations → Physical properties: calculates properties
- Solvation models → Physical properties: contributes properties
- Energy corrections → Physical properties: corrects results
- Physical properties → Result output: formats results
- Model parameters → Parameter and benchmark data: uses datasets