tddft: time-dependent density functional theory
Contents
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
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
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.
irsf
Unused.
irso
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.
insf
inso
imatnsf
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