vibronics | Vibronic spectrum simulation package

vibronics is a C++ library. vibronics has no bugs, it has no vulnerabilities, it has a Strong Copyleft License and it has low support. You can download it from GitHub.

The time-independent approach to simulate vibronic spectrum is to diagonalize the vibronic Hamiltonian. This program adopts diabatic electronic state and harmonic oscillator direct product vibrational basis, under which framework the vibronic Hamiltonian is written as. so that H^harmonic is diagonal with harmonic oscillator eigenvalues, while H^anharmonic can be very sparse in usual applications. For integral purpose, the dependency of H^anharmonic on molecular geometry is fitted as a polynomial of normal modes. In usual cases where the polynomial order is low (2nd order + few higher order terms), H^anharmonic is almost a band matrix, making Lanczos algorithm extremely efficient.