group_molecules.plot_transition_density#

group_molecules.plot_transition_density(grid_points=(40, 40, 40), delta=3, opacity=0.5, factor=1, with_radius=True, opacity_radius=1, factor_radius=.3, cutoff=.2, screenshot_button=True, window_size_screenshot=(1000, 1000))#

Plot the Transition Densities of each molecule. All the AO and the MO will be calculated on the grid if they were not calculated. The grid is defined by the number of grid points and around the molecule. The delta defines the length to be added to the extremities of the position of the atoms.

Parameters:

  • grid_points (list of 3, optional) – The number of points for the grid in each dimension. By default (40,40,40)

  • delta (float, optional) – The length added on all directions of the box containing all atomic centers. By default 3

  • opacity (float, optional) – The opacity of the plot. By default .5

  • factor (float, optional) – The factor by which the plotted_property will be multiplied. By default 1

  • with_radius (bool, optional) – Chose to show the radius and the bonds between the atoms or not. By default True

  • opacity_radius (float, optional) – The opacity of the radius plot. By default .8

  • factor_radius (float, optional) – The factor by which the radius will be multiplied. By default .3

  • cutoff (float, optional) – The initial cutoff of the isodensity plot. By default .2

  • screenshot_button (bool, optional) – Adds a screenshot button. True by default

  • window_size_screenshot (tuple, optional) – The size of the screenshots. By default (1000,1000)

Returns:

None – The plotter should display when using this function

Notes

The transition densities are defined as :

\(\rho_0^k = \sum_i c_i (Occ_i(r) * Virt_i(r))\)
With the sum being on all the transitions of the excitation, \(Occ_i(r)\) and \(Virt_i(r)\) being respectively the occupied and the virtual molecular orbitals considered in the transition, and \(c_i\) the coefficient of the transition.

Examples

For a TD-DFT calculation output :

STATE 1: E= 0.148431 au 4.039 eV
18a -> 20a : 0.5000 (c= 0.7071)
19a -> 21a : 0.5000 (c= -0.7071)
The transition density will be :
\(\rho_0^1 = c_1 (\psi_{18}(r) * \psi_{20}(r)) + c_2 (\psi_{19}(r) * \psi_{21}(r))\)
with \(c_1 = 0.7071\) and \(c_2 = -0.7071\)