Calculate IR spectra, Raman, VCD, ROA

Infrared spectra

Vibrational frequencies and thermodynamic properties at the density functional level are available for molecules (ADF) and periodic systems (BAND). Analytic frequencies are available for GGAs in ADF, and for any other functional, or for any other module are computed via AMS via an efficient double parallelization scheme.
IR spectra and vibrations can also be calculated with our fast electronic structure methods DFTB and MOPAC. IR spectra and molecular vibrations are conveniently visualized with the integrated graphical interface (see Tutorial).

VCD analysis

Raman spectra and vibrational optical activity

With ADF, static and resonant Raman spectra can also be calculated, as well as vibrational circular dichroism (VCD) and (Resonance) Raman Optical Activity (R)ROA.
Extensive VCD analysis tools (tutorial) help with assigning the absolute configuration.

For the vibrational analysis of a small part of a large systems, the mobile block Hessian (MBH) method can be used, which treats spectator parts as rigid blocks. Fast VCD spectra are also possible with DFTB.

Vibrational progression Pt OLED emitter

Franck-Condon factors

Overlap between vibrational states of two electronically differing states, Franck-Condon factors (FCFs), can be computed in ADF. Frequencies of excited states can be calculated with TDDFT, so that the vibrational progression of a one-electron excitation may be modeled. Likewise, FCFs yield accompanying vibrational transition probabilities for spin or charge transfer transitions.

TDDFTB offers fast excited frequencies (and thereby FCFs) for systems where repulsive parameters are available.
Try for yourself!

Videos demonstrating IR spectra

DFTB tutorial including IR frequencies (2019 version)

Webinar by Rosa Bulo showing MD-DFTB to simulate FT-IR spectra

Demo by Fedor Goumans building a small polymer, doing a conformational search, and calculating an Boltzmann-averaged IR spectrum