TDDFT and TDHF Keywords in the Jaguar Input File

Overview
Examples

The time-dependent density-functional theory (TDDFT) and time-dependent Hartree-Fock (TDHF) methods can be used after an SCF calculation to generate information on excited states. The output includes energies, oscillator strengths and transition dipole moments for excitations from the ground state. If a spin-orbit TDDFT calculation is run, phosphorescence rates are also calculated.

The keywords for the TDDFT or TDHF calculation are listed in Table 1. A TDDFT calculation is performed if a density functional has been specified, otherwise a TDHF calculation is performed. The rest of the calculation should be set up as an SCF calculation.

For a closed-shell system, you can choose to generate singlet excited states or triplet excited states, or both. The states are spin-adapted. If you are using the spin-orbit ZORA Hamiltonian (relham=zora-2c), Kramers-restricted excited states are generated, and you must have iuhf=0 as unrestricted TDDFT with spin-orbit coupling is not permitted. TDDFT with the spin-orbit ZORA Hamiltonian is called SO-TDDFT.

You can run TDHF or TDDFT calculations on open-shell systems with a UHF or UDFT reference function (but not SO-TDDFT or SO-TDHF, i.e. with relham=zora-2c). These calculations generate all singly-excited states, including states of higher or lower spin arising from a single spin flip, but there is no spin adaption.

In conjunction with igeopt=1, you can run a geometry optimization on an excited state generated by TDDFT (but not SO-TDDFT). If the ground state is a closed shell, you can choose to optimize the singlet or the triplet state with rsinglet or rtriplet set. The target state is set with the target keyword.

Electronic circular dichroism spectra can be generated for singlet excitations with TDDFT in the Tamm-Dancoff approximation, by setting the ecd keyword. As the spectra are conformation-dependent, a Boltzmann average over conformers is needed. For this purpose, it is recommended to use the spectroscopy.py script, or run the Circular Dichroism Workflow from Maestro. See Vibrational and Electronic Circular Dichroism Spectra for more information.

You should not normally need to set nrestart, because the program determines how many iterations it can do with the amount of memory available.

You should use the ittdft keyword, as it selects a much faster and more accurate algorithm. The old icis keyword is deprecated and may be removed in a future release.

Table 1. Keywords for TDDFT and TDHF calculations
Keyword	Value	Description
itddft	0	Do not do a TDDFT or TDHF calculation.
	1	Do a TDDFT or TDHF calculation.
itda	0	Use the full linear response in TDDFT calculations
	1	Use the Tamm-Dancoff approximation (TDA) in TDDFT calculations, do a CIS calculation for HF wave functions.
icis	0	Do not do a CIS or TDDFT calculation with the old implementation.
	1	Do a CIS or TDDFT calculation with the old implementation. Deprecated. Use itddft instead.
rsinglet	0	Do not calculate restricted singlet excited states.
	1	Calculate restricted singlet excited states. Only applies if iuhf=0, and only valid for a closed-shell reference. rsinglet=1 is the default if neither rsinglet or rtriplet is specified. Ignored with relham=zora-2c.
rtriplet	0	Do not calculate restricted triplet excited states.
	1	Calculate restricted triplet excited states. Only applies if iuhf=0, and only valid for a closed-shell reference. Ignored with relham=zora-2c.
rgeneric	0	Do not calculate Kramers-restricted excited states (i.e. including spin-orbit coupling).
	1	Calculate Kramers-restricted excited states. Only applies if iuhf=0, and only relevant for a closed-shell reference with spin-orbit coupling (relham=zora-2c); ignored otherwise.
nroot	>0	Number of roots to find. This number is used for both triplet and singlet states, if calculated. Default value is 1.
target	>0	Optimize the geometry of the specified excited state when running with igeopt=1. Must not be greater than nroot. Default value is 1.
rcontd	5.0e-3	Convergence criterion for the norm of the residual vector
econtd	5.0e-5	Convergence criterion for the change in energy
nrestart	>0	Number of iterations before restarting
	0	Determine number of iterations before restarting automatically
mitertd	32	Maximum number of iterations used
itda_autorestart	0	If a full TDDFT job fails with a negative eigenvalue of A-B (or (A-B)^1/2(A+B)(A-B)^1/2), exit with an error recommending the use of itda=1 to rerun the job with the Tamm-Dancoff approximation.
	1	Automatically restart a full TDDFT job with the Tamm-Dancoff approximation, in cases where the job fails with a negative eigenvalue of A-B (or (A-B)^1/2(A+B)(A-B)^1/2)
tddft_hso	0	Do not calculate spin-orbit matrix elements between singlet and triplet states.
	1	Calculate spin-orbit matrix elements between the triplet states and the singlet states. The calculation must be run on a closed-shell molecule with the scalar ZORA Hamiltonian (relham`=zora-1c` or `zora-scalar`), and rsinglet=1 and rtriplet=1. Matrix elements are reported in the output file for all three magnetic sublevels (M_S values) of the triplet states, as these are in general different; the matrix elements are complex.
tddft_nto	0	Do not calculate natural transition orbital (NTO) participation ratios.
	1	Calculate natural transition orbital (NTO) participation ratios, according to equation 8 in ref. 278. This keyword can be set in TDDFT or SO-TDDFT calculations.
icalcexdip	0	Do not calculate excited state dipole moments.
	1	Calculate and print excited state dipole moments. Not available with SO-TDDFT.
phosphotmp	298.0	Temperature for calculation of average phosphorescence rates. Phosphorescence rates require the spin-orbit ZORA Hamiltonian (relham`=zora-2c` or `zora-so`).
solv_refr	1.4241	Refractive index of the solvent for calculation of solvent-corrected average phosphorescence rates. The default value is for CH₂Cl₂. Phosphorescence rates require the spin-orbit ZORA Hamiltonian (relham`=zora-2c` or `zora-so`).
ecd	0	Do not calculate electronic circular dichroism spectra.
	1	Calculate electronic circular dichroism spectra [279]. The calculations are performed in the velocity representation. This keyword requires rsinglet=1.
ecd_write_vel	0	Do not write out electronic circular dichroism data in the velocity formalism.
	1	Write out electronic circular dichroism data in the velocity formalism. This is the recommended formalism.
ecd_write_len	0	Do not write out electronic circular dichroism data in the length formalism.
	1	Write out electronic circular dichroism data in the length formalism. The length formalism is not invariant to rotation or translation of the molecule, so it is not recommended.
tddft_props_mae	0	Do not write excitation energies, oscillator strengths, and transition dipole moments to the Maestro file as properties.
	1	Write all excitation energies, oscillator strengths, and transition dipole moments to the Maestro file as properties.
tddft_ometric	0	Do not calculate the orbital overlap metric.
	1	Calculate the orbital overlap metric, which can be used to assess the quality of TDDFT excitations.

TDDFT and TDHF Keywords in the Jaguar Input File

Excited State Calculation Examples