Replace or supplement LHO modes with anharmonic potentials (e.g., Morse oscillator). This enables modeling of more realistic vibrational modes where anharmonicity matters.
What needs to be implemented
- Anharmonic mode type —
MorseMode or AnharmonicMode with Morse potential parameters (dissociation energy, width)
- Numerical Franck-Condon factors — analytic FC factors only work for LHO; anharmonic modes need numerical overlap integrals of eigenstates
- Eigenstate computation — solve 1D Schrödinger equation for the Morse/anharmonic potential (DVR method or analytical Morse eigenstates)
- Integration with Molecule/Aggregate —
Mode becomes abstract, HarmonicMode and MorseMode are subtypes
Impact
Changes the Mode struct fundamentally. Needs careful design to maintain backward compatibility.
Proposed files
src/anharmonic.jl — anharmonic mode types and numerical FC factorstest/test_anharmonic.jl — tests, verify LHO limit recovers analytic FC factors
Replace or supplement LHO modes with anharmonic potentials (e.g., Morse oscillator). This enables modeling of more realistic vibrational modes where anharmonicity matters.
What needs to be implemented
MorseModeorAnharmonicModewith Morse potential parameters (dissociation energy, width)Modebecomes abstract,HarmonicModeandMorseModeare subtypesImpact
Changes the
Modestruct fundamentally. Needs careful design to maintain backward compatibility.Proposed files
src/anharmonic.jl— anharmonic mode types and numerical FC factorstest/test_anharmonic.jl— tests, verify LHO limit recovers analytic FC factors