[molpro-user] Atom excitation energies and transition moments

[Pablo Avaria]

Dear Tatiana,
thank you for your reply.I noticed that the eom-ccsd results depend on the basis set used.For example, for 2.2 state for He
         excit. en.    right dipole trans.
 avtz  2.24               -0.18
avqz  1.89               -0.48
av5z  1.67                0.51
av6z  1.51                0.52
tav6z 0.85                0.28


Just in case my input:
 memory,50,m basis=av6z                                                                      geometry={he}                                                                   
 hf                                                                            ccsd                                                                             eom,2.2,trans=1                                                                  
Am I doing anything wrong?
Pablo


 

    On Friday, August 4, 2017 5:56 PM, Tatiana Korona <tania at tiger.chem.uw.edu.pl> wrote:
 

 Dear Pablo,

If you want to interpret excited states in EOM-CCSD in more detail, first you 
can look at main excitations given in the form n.sym1 -> r.sym2 (for single 
excitations), so you can interpret your 3.1 state according to the main 
excitations listed under the excitation energy in the output. It is of course 
sensible to print or save virtual orbitals, too, in order to recognize what type 
of the orbital stays under "r.sym2".

You can also make a population (or natural-orbital) analysis of the 
excited-state density, see $molpro/example/hf_eom_prop.com

or save densities in the CUBE format

memory,2,m
gthresh,twoint=1.e-14,energy=1.d-8
gprint,orbital=10
basis=avdz

geometry={
O
H1,O,r
H2,O,r,H1,th
}

! MP2/vtz optimization:
r=0.959 Ang
th=103.5

{hf
save,2100.2}

{ccsd
dm,6000.2
eom,-5.1,-4.2,-4.3,-4.4,trans=1
}


cube,water11.cube;density,record=6000.2,state=1.1
cube,water23.cube;density,record=6000.2,state=2.3


and then use e.g. Gabedit to visualize the difference density (den2.3-den1.1).

Best wishes,

Tatiana


  On Thu, 3 Aug 2017, Pablo Avaria wrote:

> Hello,
>
>
>
> I need to calculate the excitation energies, dipole and quadrupole transitions moments
> between ground and excited states as well as between different excited states for an atom.First I ran some tests for He atom. 
>
> The EOM-CCSD method with the card "eom,-5.1,start=6000.2,save=6000.2,trans=1"
> gives the following excitation energies: Results for state  2.1: 20.936 eV Results for state  3.1: 37.788 eV
> The first one looks likes the optical forbidden transition 1s^2 1S - 1s2s 1S What about the state 3.1?
> The TD-DFT method with the card "df-tddft,orb=2100.2,nexcit=10"gives the following values 25.997 eV and 40.775 eV which I am not able to interpret. 
> Are these methods applicable for my problem?Or should I use define each state manually with occ-closed-wf commands and use a method like CASSCF?
> Would it possible to get an example, let's say for dipole-allowed 1s^2 1S - 1s2p 1P transition?Thank you in advance for you help!
> Pablo
>
>

Dr. Tatiana Korona http://tiger.chem.uw.edu.pl/staff/tania/index.html
Quantum Chemistry Laboratory, University of Warsaw, Pasteura 1, PL-02-093 Warsaw, POLAND

   
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