Questions tagged [td-dft]
Questions related to Time-dependent density functional theory (TDDFT) is a quantum mechanical theory used in physics and chemistry to investigate the properties and dynamics of many-body systems in the presence of time-dependent potentials.
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N2 HOMO-LUMO Gap calculation
I am thinking about calculating the HOMO-LUMO energy gap for $\ce{N2}$ molecule.
I thought I could model this as a particle in a box problem to find $E_\text{HOMO}$ and $E_\text{LUMO}$.
The formula I ...
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How to calculate transition dipole moment from two known wavefunctions
I am interested in calculating the transition dipole moment (TDM) from the information from two wavefunctions of different states. This is somewhat similar to calculating the molecular dipole moment ...
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Is there an anisotropy factor (g factor) for TDDFT Abs and CD calculations?
Experimentally, anisotropy factor is calculated by dividing the CD spectra by the absorbance spectra multiplying by a factor of 32980 (in order to get a nondimensional quantity)
Theoretical ...
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High-temperature DFT
Why is it so difficult to perform DFT calculations that consider temperature?
I have seen that time-dependent DFT is needed to model systems at high temperature.
Why is this the case? What about ...
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Open shell TDDFT excitaion contribution
If I have a open shell system (10 alpha electrons and 9 beta electrons) and running TDDFT calculations, is it possible to have a 9a→10b transition? Or does it have to be 9b→10b? Because both exciation ...
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Oscillator Strength and Absorption Intensity in TDDFT
When I run a linear-response time-dependent DFT calculation in my favourite electronic structure program, for each excitation I'm given an oscillator strength, $f_i$, and transition dipole moment $$\...
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Changing the level of theory for organometallic compounds
I'm finishing my Ph.D. in Inorganic Chemistry and having a debate with my supervisor. The work in question have two organometallic compounds A and B. The structures are based on X-Ray Diffraction, so ...
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Absorption and emission at same wavelength?
Is it possible for a molecule to absorb and emit at the same wavelength? What is the reason behind it?
I’m working on charged tin porphyrins and got the excitation and emission (fluorescence) ...
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How to retrieve excited state molecular orbital coefficients in Gaussian?
Currently I am doing TD-DFT calculations in Gaussian and want to calculate transition dipole moment for $S_1$ transition manually. However, I do not manage to retrieve molecular orbital coefficients ...
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Is it rigorous enough to change a DFT functional after geometry optimization to calculate excited state properties?
I have done the geometry optimization with the B3LYP functional, however, there is a need to calculate the excited state energy, so the CAM-B3LYP functional should be better suited for that. Do I need ...
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Can you explain DFT and TDDFT functioning (math aside)? [closed]
I have been recently reading a lot on the quantum mechanical theory regarding Density Functional Theory, DFT, and Time Dependent Density Functional Theory, TDDFT (Oscillatory and Rotatory Strengths in ...
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Interpretation of TD-DFT results
For the first time I'm doing TD-DFT calculations (wB97XD functional) in Gaussian 09 for an open-shell system and the results look like the hell of a mess for me. The molecule is rather big, so I ...
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Is there a relation between transition density and density differences?
When I have an excited state, is there a relation between the transition density associated with this electronic transition and the density difference between the excited state density and the ground ...
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Calculating singlet-triplet gap and open-shell singlet character
I am trying to calculate the singlet-triplet energy gap ($S_0-T_1$) of a conjugated system (18 atoms). For the singlet $S_0$ state, assumed to be closed shell, the Gaussian options were
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Excited-states properties with traditional density functional theory
Recently I was shown the book "Density Functional Theory II, Relativistic and Time Dependent Extensions" by Nalewajski in which a chapter from E. K. U. Gross et al. is printed. [1] This chapter ...
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How to interpret orbital transition in TDDFT?
Consider the following TDDFT run with GAMESS:
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Which is most reliable excitation energy: LUMO-HOMO energy or TD-DFT excitation energies?
After running a TD-DFT , we can calculate the HOMO-LUMO difference and then calculate the the excitation energy.
Another approach is just simply pick the energies calculated in the TD-DFT and use ...
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How to interpret TD-DFT results for finding λmax and amplitude
I am trying to understand how to interpret the TDDFT results ( I know there is another post for this but it does not answer my question ). Here is part of the result from GAMESS:
I downloaded ...
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How to Locate the Excited State Dipole Moment in Turbomole Output (TD-DFT)
I want to calculate the dipole moment for the first excited state with a Q.C. program (TURBOMOLE: TD-DFT). The calculation lists the following output:
ground state total dipole moment:
...