#
Excited state calculations with time-dependent DFT method

###
Gaussian

Also open-shell ground state.

Use keyword `TD` (G98 manual p. 155).

Chapter 9 (7, p. 173) in *Exploring chemistry with electronic structure
methods* gives a detailed description of the CIS method which has similar
input and output.

Use a normal SCF calculation input file and add in the final step:

`TD(Nstates=12,Root=5) Density Pop=Full`

where

`Nstates` is the number of interesting states and

`Root` is the root of interest (for population analysis and
geometry optimisation)

Only for a closed-shell ground state