#!/bin/sh # Calculation of the excitation energies of beta-Carotene using the TD-DFT+TB # method. This method is meant for GGA or LDA functionals. In this example PBE # is used during the SCF. In the the calculation of the excitation energies the # TD-DFTB+TB method is used in which the required integrals are approximated in # the same way as in a TD-DFTB calculation. Symmetry NOSYM is required. # The key MODIFYEXCITATION allows to remove single orbital transitions based on # certain criteria. For example, for a large calculation, one can combine # several of the filtering techniques with the key MODIFYEXCITATION. If one uses # the next input, only the lowest 10000 single orbital transitions are used # (which have the lowest orbital energy differences). Out of these 10000 the # single orbital transitions with an oscillator strength smaller than 0.001 are # removed, and single orbital transitions are removed that have an energy # difference larger than 1.0 Hartree. In the space of single-orbital transition # that are left the lowest 1000 eigenvectors are calculated. # ModifyExcitation # UseOccVirtNumbers 1 10000 # OscStrength 0.001 # UseOccVirtRange 0.0 1.0 # End # Excitations # TDDFTB # OnlySing # Lowest 1000 # End # In the actual example only single orbital transitions with an oscillator # strength smaller than 0.001 are removed, which one might do if one is # interested only in excitation energies with a high oscillator strength. $AMSBIN/ams <