tddft: time-dependent density functional theory

Time dependent DFT/HF calculation. Support Full TDDFT, TDA and RPA.

Quick guides

The following examples give the minimal inputs for starting TD-DFT calculations.

1. Closed-shell Systems : R-TD-DFT

2. Open-shell Systems : U-TD-DFT and spin-adapted TD-DFT for spin-conserving excitations

3. Open-shell Systems : Spin-flip TD-DFT for spin-flip excitations

4. TD-DFT with SOC

General keywords

imethod

isf

itda

idrpa

ispa

ialda

thrdab

itest

icorrect

itrans

iro

icv

ioo

iksf

iact

elw

eup

idiag

ndiag

aokxc

States specification

iext

next

Save eigenvectors

istore

Integer: specify the file no. to store TDDFT information

lefteig

By default, in TD-DFT the left eigenvector X-Y is also stored.

output eigenvector control

nprt

cthrd

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TD-DFT/SOC

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TD-DFT/SOC and Property evaluation

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isoc

=1, Only work for closed-shell case (NOT recommended!)

=2, General SOC state interaction

=3, just print SOC matrix elements between two spin-free states

irsf

Unused.

irso

insf

inso

imatsoc

Define SOC matrices need to be calculated. Input format looks like

...
#SCF calculation for the ground state S0. It is a singlet.
$scf
spin
 0
...
$end

#First TDDFT, singlets S0-S9.
$tddft
imethod
 1
isf
 0
iext
 10
....
$end

#Second TDDFT, triplet T1-T10
$tddft
imethod
 1
isf 
 1
iext
 10
$end

$tddft
....
imatsoc
  7
0 0 0 2 1 1
0 0 0 2 1 2
1 1 1 2 1 1
1 1 1 2 1 2
1 1 2 2 1 1
1 1 2 2 1 2
2 1 1 2 1 1
2 1 1 2 1 2
$end

In this input, 7 means seven of SOC matrices will be calculate. Here, it is very tricky to specify states. First, "0 0 0" always treat as the ground state. Second: For other states, three numbers "n m n" represent "ith-tddft", "symmetry" and "ithstate" respectively. Therefore, the first matrix element "0 0 0 2 1 1" means SOC matrix of <S0|HSOC|T1>. The third matrix element "1 1 1 2 1 1" means SOC matrix <S1|HSOC|T1>. Here, the first "1" in bra state "1 1 1" means the state from first TDDFT calculation. The second and third "1" in the bra state "1 1 1" means this state has spatial symmetry "1" and is the first excited state.

imatrsf

Unused.

imatrso

Define transition dipole need to be printed between to states. Input format looks like(notice we omit other input in TDDFT module)

$TDDFT
...
irso
1
imatrso
5
1 1
1 2
1 3
1 4
1 5
...
$END

Here, "irso" is set to 1 to enable transition dipole moment calculation. Then, "imatros" is specified to define transition dipole moments need to be printed. The number "5" require transition dipoles between 5-pairs of states to be print. The following 5 lines define which pairs will be printed. Here, we require transition dipoles between the ground state and five low-lying states are printed.

imatnsf

ifgs

nfiles

isgn

ivo

idiag

TD-DFT/SOC can use Davidson's algorithm also, along with a specification for the no. of states by iexit.

iact

=1, allows to use active space specification for the projected active-orbital SOC Hamiltonian (P*HSOC*P), eup can be specified in (eV) to give a cut off to define active physically interested excited states.

Stability analysis

isab

isave

memory control

memjkop

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