# Vibrations#

**Vibrations**from the list of possible project types implemented in ASAP.

Then click on the *Parameters* icon to open the Vibration parameters widget.

The project parameters that can be tuned are:

**Number of points**. Number of displacements per atom and cartesian coordinate. The number of displacements supported are 2 and 4.Number of points 2: Displacement of each atom by the values +\(\Delta\) and -\(\Delta\) for each cartesian coordinate.

- Number of points 4: Displacement of each atom by the values +\(\Delta\), +two times \(\Delta\), -\(\Delta\), and -two times \(\Delta\) for each cartesian coordinate.

Notice that the displacement is applied to each atom in the configuration. When performing a vibration project, one may wish to keep some degrees of freedom in the system fixed. We refer the user to section ASE GUI in ASAP for information of setting constraints.

**Displacement magnitude h (Å)**. Parameter giving the magnitude of displacements. Unit: Å

Click on the *Calculator* icon to select the computational engine to be used
during vibration calculation.

*Run*icon to open Run widget. Then press the

**Run**button to submit the vibration calculation.

*Calculator output*in Run widget shows the complete calculation output in real time.

In addition, the tab *Task output* in Run widget shows relevant information of
Vibration output in real-time.

## Vibrations workflow: Analysis#

When the calculation is completed, select **Exit and analyse** to open the
analysis widget.

**Density of vibration modes**The density of vibrational modes is defined by \(Density(w) = \sum_i \delta(w-E_i)\), where w is frequency at which the density of vibrational modes is computed, the sum runs over vibrational modes i, \(E_i\) is frequency of the vibrational mode i. \(\delta\)(w) is the Dirac \(\delta\)-function.

You can adjust the following parameters in the representation of density of vibrational modes:

Method. Gaussian or Lorentzian representations of the Dirac \(\delta\)-function.

Minimum and Maximum. They are the start and end values of the Gaussian/Lorentzian in units of eV, meV, Ry, Ha, THz, K, and cm

^{-1}.Width at half maximum. Broadening defined by the full-width-at-half-maximum in both representations (Gaussian and Lorentz) of the \(\delta\)-function.

**Vibration modes**

This analysis option presents the computed vibrational modes list alongside their corresponding energies. Additionally, it offers the zero-point vibrational energy (ZPVE).

To see an animation of one of the computed vibrational modes, select it first
from the list, and then click on the *View animation in 3D editor* button. The
following settings can be tuned before viewing the animation:

Magnitude: Temperature (in K) associated to the energy (E(\(\nu\))) of the selected vibrational mode.

Force scale: Parameter only available when

*Set scale manually*tick-box is activatedNumber of images: Number of images that will be included in the animation.

Play the movie to visualise the animation of the selected vibrational mode.