Demo: Quantum Chemistry
QM Workflow

Ligand-X Demo

Demo: Quantum Chemistry

Perform advanced DFT calculations on ligands to compute electronic properties, optimize geometries, and generate accurate partial charges.

Video Walkthrough

Coming Soon: Video walkthrough demonstrating quantum chemistry calculations in Ligand-X.

Data Flow Pipeline

When you submit a quantum chemistry calculation, your data flows through these stages:

1. Molecule Preparation (0–10%)
  • Parse SDF/MOL structure
  • Add hydrogens if missing
  • Convert to Psi4 molecule format
  • Set charge and multiplicity
2. Geometry Optimization (10–60%)
  • Initial single-point energy
  • DFT optimization (B3LYP/6-31G*)
  • Convergence criteria check
  • Final optimized geometry
3. Property Calculation (60–90%)
  • Single-point at optimized geometry
  • Compute molecular orbitals (HOMO/LUMO)
  • Calculate dipole moment
  • Generate electrostatic potential
4. Charge Analysis (90–100%)
  • Mulliken population analysis
  • RESP charge fitting (optional)
  • Export partial charges
Results
  • Optimized geometry (XYZ, SDF)
  • HOMO-LUMO energies and gap
  • Dipole moment (Debye)
  • Partial charges per atom
  • Total energy (Hartree)
  • Orbital visualization

Tools Used

Stage Tool Purpose
Parsing RDKit ORCA-parser Molecule parsing, format conversion
QM Engine ORCA DFT calculations
Analysis Python Post-processing of results

Workflow Steps

  1. Upload Ligand: Provide SDF file or draw with Ketcher
  2. Select Method: Choose DFT functional and basis set
  3. Configure Options: Optimization, properties, charges
  4. Submit Job: Calculation runs on QC worker
  5. Monitor Progress: Watch optimization converge
  6. View Results: Inspect orbitals, charges, properties

Calculation Options

Option Description
Method DFT functional
Basis Set Atomic orbital basis
Geometry Optimization Find minimum energy structure
Single Point Energy at fixed geometry
HOMO-LUMO Frontier orbital energies
Dipole Moment Molecular polarity
Partial Charges Atomic charge distribution
ESP Surface Electrostatic potential map

Common Methods

Method Description Use Case
B3LYP/6-31G* Standard DFT General purpose
ωB97X-D/def2-SVP Dispersion-corrected Non-covalent interactions
HF/STO-3G Minimal basis HF Quick estimates

Output Properties

Property Units Description
Total Energy Hartree Electronic + nuclear energy
HOMO eV Highest occupied orbital
LUMO eV Lowest unoccupied orbital
HOMO-LUMO Gap eV Reactivity indicator
Dipole Moment Debye Molecular polarity

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