Harmonic spectra of Coronene monomer and dimer

A

Keep the geometry of coronene but replace the dynamics by a simple optimization.

Explore the deMon.out file and visualize the deMon.mol trajectory

B

Perform a frequency analysis on the last geometry (copy-past from
deMon.mol and remove OPTIMIZATION KEYWORD)
 →  FREQUENCY
Visualise the harmonic spectrum with molden (Norm. Mod. button), and
the associated modes.
What are the active/inactive modes and why ?

C

Create the geometry of a coronene dimer with two superimposed molecules. Add a dispersion correcion to the DFTB line : → DFTB SCC DISP

Perform an optimization of the dimer (without FREQUENCY analysis).

D

Compute the frequency analysis for the optimized dimer (copy and pas
the optimized geometry).
Visualize the vibrational modes with molden in order to identify the
inter- and intra (soft and hard) molecular modes and their position in
the spectrum.
Are their imaginary frequencies (represented by negative values ? What
does it mean ?)

E

Create a dimer in a twisted superimposed form.
Optimize and compute the normal mode analysis.
What can be said from this geometry ?

F (optional)

Create and explore larger clusters.

The solutions of the tutorial (input and output files) can be downloaded here : solutions

Next step : * Temperature evolution of the electronic spectra of cationic Methylene-Pyrene Isomers