Questions tagged [td-dft]
For questions related to time-dependent density functional theory.
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What are the types of DFT?
Similar to: What are the types of charge analysis?, What are the types of bond orders?, and What are some recent developments in density functional theory?, I would like to ask: What are the different ...
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Given that Kohn-Sham DFT is strictly a ground-state method (at 0 K), how is it sufficient to describe materials in real-life applications?
Kohn-Sham DFT appears to be so popular even though it is strictly a ground-state method - all calculations are done at 0 K. How then, is it so popular when describing materials that have real-life ...
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What are the recent developments of TDDFT to simulate the excited properties of materials?
The time-dependent density functional theory (TDDFT) and the many-body perturbation method (GW@BSE) are considered as the two most popular and successful methods to describe the excited-stated ...
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What methods are available for excited state calculations in solids?
In the spirit of a succint answer (3 paragraphs maximum) to create a useful resource, what are the types of excited state calculation available for solids? Please add to the list:
Quasiparticle ...
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Validity of adiabatic approximation in TDDFT
In the time-dependent Kohn-Sham formalism the effective potential on electrons is given by
$$ v_s[\rho(\mathbf{r},t)]=v(\mathbf{r},t)+v_H(\mathbf{r},t)+v_{xc}[\rho(\mathbf{r},t)] $$
where, $v(\mathbf{...
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What is the importance of electron interaction on dielectric response of crystals?
After obtaining the Kohn-Sham orbitals from a plane-wave-based self-consistent-field calculation, the dipole matrix elements could be calculated in order to determine electro-optical properties such ...
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How can reactivity indices be calculated in a time-dependent scheme?
Many reactivity descriptors can be obtained from ground state (or static) DFT as energy derivatives respect to the number of electrons, $N$, and the external potential, $v(\mathbf{r})$, like chemical ...
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What are the recent developments of GW@BSE to simulate the excited properties of materials?
A twin question related to the TDDFT method is asked in another post. But any comparisons between both methods in recent developments are welcome.
The time-dependent density functional theory (TDDFT) ...
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Is there a software that has implemented forces of TDDFT calculations for solids?
I'd like to investigate the structural relaxations of the excited state for periodic systems. BSE and TDDFT are two promising methods for this purpose. While there is a discussion on forces with BSE ...
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Is there an example in which TD-DFT was successful in describing photophysical or photochemical processes?
Time-dependent Density Functional Theory has been around for quite a while now, seeing Density-Functional Theory for Time-Dependent Systems, and so it has been developed extensively, implemented in ...
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How do you calculate the change in dipole moment from ground to first excited state using ORCA?
How do you calculate the change in dipole moment from the ground to first excited state using ORCA? I have done DFT to get the dipole moment at the ground state and TDDFT of this neutral molecule. How ...
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Regarding oscillatory strength theoretical units to experimental ones
The output of Gaussian rotatory and oscillatory strength intensities, plus a gaussian/lorentzian fit, translates to a theoretical CD/UV-vis spectra.
In order to try and compare with experimental ...
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Deviation caused by using DFT in Non-Adiabatic Molecular Dynamics
To calculate the excited state properties and processes of semiconductors (e.g. during the photocatalysis process), can be important. Non-Adiabatic Molecular Dynamics (NAMD) is one of the popular ...
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I ran TDDFT on some small molecules. For some files, the ORCA output files cut short and contain no absorption data. What could be the reason? [closed]
Below is just the end of the output file, and the top of the input file. This is for the molecule FDICTF. The calculation did not run out of time. I ran a batch of 15 molecules, all with same ...
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Is there an example where TD-DFT fails to provide sufficient accuracy for a small system, where RI-CC2 is sufficient?
Time-dependent density functional theory (TD-DFT) is considered to be more efficient (in terms of its accuracy/speed ratio) than alternatives such as the approximate coupled-cluster singles and ...
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Understanding emission spectra using TDDFT calculation
I did a TDDFT calculation to get the emission spectra of my molecule. Here are the first five roots for the emission calculation:
...
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Is there a software that has implemented forces of BSE calculations for solids?
I'd like to investigate the structural relaxations of the excited state for periodic systems. It seems BSE is a practical method that has already been implemented in many codes for static calculations....
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Understanding absorption spectra using TDDFT calculation in NWCHEM
I did a TDDFT calculation using B3LYP functional and ground state optimized structure in NWCHEM. The TDDFT portion of the output is the following:
...
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Reading complex potential into CP2K
Is it possible to read a complex potential into CP2K? I have generated a potential using FDTD at a given frequency, which results in a complex result. The potential is to be read in to a real time ...
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Is it reasonable to calculate TDDFT excitation energies at a geometry optimized with a different method?
I am working on a project where I have to calculate the TDDFT excitation energies of organic molecules (to compare to the experimental UV/visible i.e. optical absorption spectrum). Now, if I ...
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Any software that could do surface hopping?
I am trying to understand how to do the time-dependent simulation of the electron transfer, I find that the popular method is surface hopping, but I am not sure if there is any software that could ...
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Is it possible to do TD-DFT/6-31G+(d,p) calculations on a laptop?
In the recent publication:
"Density Functional Theory Calculation on the Structural, Electronic, and Optical Properties of Fluorene-Based Azo Compounds",
the author claimed to have used ...
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Is there an anisotropy factor (g factor) for TDDFT absorption and circular dichroism calculations?
Experimentally, anisotropy factor is calculated by dividing the CD (circular dichroism) spectra by the absorbance spectra and multiplying by a factor of 32980 (in order to get a dimensionless quantity)...
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Quantum Chemistry software that can calculate nonadiabatic coupling vectors between excited states using DFT/TDDFT
I am looking for software that can calculate the first-order non-adiabatic coupling vector $$\vec \tau_{ij}=\langle \varphi_i|\nabla_R\varphi_j\rangle$$ between excited electronic singlet states using ...
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How to extract transition density cube from .fch file in Gaussian?
I have been trying to extract the transition density cube of a simple molecule, $\ce{H_2O}$. I did a regular geometry optimization and then TD-DFT calculation with a keyword ...
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What could be the possible causes of the energy difference in the following calculation using Octopus (TDDFT) code? [closed]
I am trying to do a simple ground state energy calculation of methane molecule using the Octopus (TDDFT) code. The example is already available in the octopus manual. ...
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Different types of transition dipole moment in ORCA output
In the ORCA output for a TD-DFT calculation, there are two types of spectra printed. One is called "transition electric dipole moment" and "transition velocty dipole moment".
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How to assign UV-vis maximum absorption wavelength theoretically by using td-DFT?
I'm currently working on the simulation of Uv-vis absorption spectra of some organic compounds, while performing TD-Dft the log file that we got contains the values of deltaE of the transition,...
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Accurate electron-hole localization for charge-transfer transitions
I'm studying the nature of electronic excitation in conjugated organic dyes.
To define the donor and acceptor part I've run TDDFT and CIS calculation, they both gave similar set of configurations for ...
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Vertical transition, 0-0 transition, and experimental spectra
I am currently working on a machine learning with spectroscopy. I had learnt about the Franck-Condon principle and the vibronic coupling in photochemistry courses in my undergraduate lectures. However,...
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S1-T1 energy difference in Gaussian
I would like to calculate the energy difference between the first excited singlet and the first excited triplet of a given molecule in solvent, on Gaussian. In this publication, they state that using ...
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how can I distiguish between pi-pi* or n-pi* while doing a TDDFT calculus on gaussian?
Hi I have a system that belongs to the C1 point group which is polycyclic and contains heteroatomes ,when calculating the excited states by TDDFT and after visualising the MOs that are envolved on ...
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Does it make any sense to run a TD-DFT calculation with Finite-Temperature SCF active?
I recently received the task to investigate what is happening in a fluorescent molecule in different temperatures. How the electronic population is changing and how is this affecting the electronic ...
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Can a spin-flip TD-DFT singlet ground state wavefunction be written as a sum over MOs with occupancy information?
Using collinear spin-flip(SF) TD-DFT with the Tamm-Dancoff approximation, BHanHLYP and a simple test molecule (ethene, with a singlet ground state).
It's my understanding, using ethene as an example, ...
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simulate dynamic response to laser impulse with TDDFT in SIESTA [closed]
I am trying to simulate the dynamic response of semiconductors to laser impulse, but I am not sure how to do it with TDDFT in siesta, I checked the siesta-doc, and it seems I need to construct an ...
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How to calculate singlet-triplet splitting energy with TD-DFT in ORCA?
I wish to reproduce the results from this paper by Truhlar and co-workers, where they treat a spin-forbidden reaction by considering two effective states coupled by a semi-empirical spin-orbit ...
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Absorption spectra with Gaussian [closed]
I want to calculate the absorption spectra of molecules (and possibly ions) with TD-DFT.
I have used Gaussian in the past and, to my knowledge, the application of TD-DFT is implemented in this code. ...
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Is a D-Wave quantum computer able to do TD-DFT calculations?
I was reading this paper (Computing molecular excited states on a D‑Wave quantum annealer) and wondering if I can make a QUBO model for the equations used in the TD-DFT energy calculation for the ...
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1
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A different way to optimize triplets?
I am studying a system with TD-DFT method implemented in Gaussian. I am not sure whether this two inputs are adequate by the mean of output - optimization of T1?
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Which component of the dielectric tensor is used in generating EELS in TDDFT? [closed]
Electron Energy Loss Spectroscopy (EELS) comes from the imaginary part of the inverse dielectric function $-\text{Im}[\varepsilon^{-1}(q, \omega)]$. If the dielectric function is actually a tensor and ...
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Gaussian does not reproduce UV-Vis spectrum [closed]
I am performing some TD-DFT calculations to reproduce the UV-Vis spectrum of a molecule using Gaussian. After optimizing the structure, I performed a TD-DFT calculation with 150 states and I tried ...
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