# Re: CCL: energy of the first excited state

• From: help]![gaussian.com
• Subject: Re: CCL: energy of the first excited state
• Date: Tue, 19 Jul 2005 15:14:59 -0400

Sent to CCL by: help]![gaussian.com
The CIS model use Hartree Fock(HF) to model the ground state and then
excited states are modeled with a linear combination of singly substituted
determinants.  So the value reported for E(CIS) is E(HF) + deltaEn  where
n=1,...nStates. are the first though nth excitation energies.  Only one
state can be studied at a time, by default the first excited state is
chosen.
So in short E(CIS) is the excited state energy, E(HF) is the ground
state.
On Tue, Jul 19, 2005 at 08:52:54AM -0400, CCL wrote:
>
> Sent to CCL by: "??????" <yangzn553]=[nenu.edu.cn>
> This is the input file
> #P cis(direct)/6-31+G** density=current opt=z-matrix gfinput iop(6/7=3)
test
> > from the output file I get the following informations
> first, Excitation energies and oscillator strengths:
>  Excited State   1:   Singlet-A'     3.8548 eV  321.63 nm  f=0.5311
>       62 -> 63         0.52533
>       62 -> 65        -0.41883
>  This state for optimization and/or second-order correction.
>  Total Energy, E(CIS) =  -794.462358789
> The other two excited states is useless for my question, so I don??t copy
it. My
> question is whether E(CIS) =  -794.462358789 is the energy of the first
excited
> state in cis/6-31??G** level.
> Second, in the last of the output file, I get HF=-794.604021. what is the
meaning
> of it, whether this one is the energy of the first excited state. What is
the
> meaning of HF.
> In conclusion, E(CIS) =  -794.462358789  and HF=-794.604021, which one is
the
> energy of the first excited state in cis/6-31??G** level.--
Douglas J. Fox
Technical Support
Gaussian, Inc.
help]![gaussian.com