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

Convergence threshold

crit_e

crit_vec

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

TD-DFT/SOC and Property evaluation

nfiles

No. of TD-DFT calculations to be loaded.

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 (without diagonalization Hsoc).

ifgs

=0, default for not including ground state (GS) in SOC treatment; =1, include GS.

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 (If the number <0, then ALL possible HSOC mat will be printed !). Here, it is very tricky to specify states:

• The string "0 0 0" always treat as the ground state.

• 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

Transition dipole between Spin-free states. The input is similar to imatsoc (but currently selected printing is not implemented). Simply use -1 to print all of them.

imatrso

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

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

Then, "imatrso" 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 first state and five states are printed.

idiag

By default, idiag=0 uses full diagonalization (preferred for small model space).

If idiag=1, then 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

Others

isgn

ivo