Questions tagged [td-dft]
For questions related to time-dependent density functional theory.
59
questions
1
vote
1
answer
108
views
Problematic optimization of excited states
I work with Orca 5.0.4 (without access to version 6.0) on a symmetric metal-centered system. I'm currently running excited state optimizations, and while S1-S3 and T1, T2, and T4 have optimized ...
- 523
1
vote
0
answers
23
views
Franck-Condon Gaussian16 Input Advice
I am currently following page 367 of the third edition of the gaussian electronic structure software textbook. I followed the procedure laid out for performing a Franck-Condon analysis, but I am ...
MrAmateurChem
3
votes
1
answer
66
views
Mixing functionals in TD-DFT opt
I work with copper complexes containing at least 100 atoms (including a single Cu, nitrogens, carbons, and hydrogens). According to Grimme's paper, the benchmark level for geometry optimization is ...
- 523
5
votes
1
answer
78
views
Do oscillator strengths matter when matching theoretical and experimental outcomes?
I use ORCA to do TD-DFT studies. The experimental maximum absorption is esteemed to 445.0nm . Benchmark computations were conducted and this is the exemplatory (part of) the output:
...
- 523
1
vote
1
answer
94
views
Should I use ZORA/DKH for my geometry optimization, or only for TD-DFT?
ORCA has implemented a scalar relativistic contracted version of def2-TZVP (with DKH or ZORA), which I used to study a copper-phenantroline system (for geometry optimization and TD-DFT).
My question ...
- 523
6
votes
1
answer
151
views
Assessing excited state lifetime with TD-DFT
My question is brief — is it possible to estimate excited state lifetimes using computational chemistry (DFT/TD-DFT) tools? I am aware this may be a rough approximation (e.g., neglecting non-radiative ...
- 523
3
votes
0
answers
24
views
DFT simulations of UV-VIS spectroscopy for Semiconducting Heterojunctions
I have a course project that involves DFT. Does anyone know of any tutorials or resources to simulate UV-Vis spectroscopy of semiconducting heterojunctions using ORCA, Quantum Espresso, or any other ...
RKVR14
2
votes
0
answers
41
views
static self-consistent calculations
How is the static self-consistent calculations different from standard self consistent field calculations? Please also explain this in context of other type of calculations e.g. single shot.
- 889
4
votes
1
answer
239
views
How to plot absorbance from a Quantum ESPRESSO optical calculation using ε1, ε2, and energy data?
I have a calculation via DFT-RPA, which calculates epsilon_2 and energy (eV). For optical property calculation, we usually plot epsilon_2 vs energy (eV). However, I need to know to convert the y-axis ...
- 751
3
votes
1
answer
79
views
optical properties in IR region
I have done geometry optimization using hybrid functional. this gives a band gap that is comparable to the experimental one. but I am also expecting my optical properties to be in IR region, but they ...
- 55
2
votes
0
answers
22
views
Error in the PH file for RAMAN and FTIR calculation
I am doing the Raman and FTIR calculations using quantum espresso, I ran the following codes
...
- 639
3
votes
1
answer
128
views
Cannot reproduce excitation energies in Orca
I do TD-DFT studies in Orca 5.0.3 on porphyrin system and hence at the very beginning I need to pick functional that reproduce excitation energies.
The experimental reported values equal: 691, 656, ...
- 51
2
votes
0
answers
25
views
How to seperate structures in bulk with connectivity from a relaxed scan in Gaussian 16?
I aim is to construct the PES for a molecule considering a specific bond length as the scan coordinate. I am using the Relaxed-Scan feature of Gaussian 16 for this using the ...
- 103
4
votes
1
answer
167
views
How do I do a PES (potential energy surface) scan for the excited electronic state?
I know how to do a PES scan for a ground electronic state. But for the nth-excited state, is it the same (i.e. an excited state optimization and just rotating the dihedral to simulate the ...
- 91
5
votes
2
answers
283
views
Trying to get concurrent results for a TDDFT calculation in Gaussian and ORCA
I am trying to do a simple TDDFT calculation in both Gaussian and ORCA from the exact same reference Geometry. I am using the same functional (making sure to use ...
- 103
3
votes
1
answer
115
views
How may I verify that my A matrix for TDA (Tamm-Dancoff Approximation of TD-DFT) from PySCF is correct?
This is a follow-up to a series of questions that I have asked here:
Is a D-Wave quantum computer able to do TD-DFT calculations? (answer was "yes, but it might not be efficient")
Inquiry ...
- 151
5
votes
1
answer
587
views
Methologies to calculate excited states in Gaussian
Referring to previous questions asked here, I would like to pose a more general question about the calculation of ΔE(S1-T1) for organic molecules with the software Gaussian16.
In particular, I have ...
- 1,349
3
votes
1
answer
191
views
Difference in energy between first excited singlet and first excited triplet with DFT in Gaussian
I want to ask a further question related to this one.
I have performed the calculations as explained and obtained a difference in energy of 0.71eV with the TDA-DFT level of theory.
Then, I tried to do ...
- 1,349
5
votes
1
answer
514
views
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 ...
- 1,349
3
votes
1
answer
187
views
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 ...
- 151
5
votes
0
answers
293
views
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 ...
- 7,161
1
vote
0
answers
152
views
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 ...
- 1,349
5
votes
1
answer
253
views
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 ...
- 327
2
votes
0
answers
40
views
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 ...
- 131
9
votes
1
answer
307
views
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 ...
- 951
4
votes
0
answers
140
views
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. ...
- 1,349
7
votes
1
answer
414
views
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,...
- 855
3
votes
1
answer
863
views
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?
...
- 523
5
votes
2
answers
1k
views
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,...
- 7,161
5
votes
0
answers
77
views
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 ...
- 2,087
5
votes
1
answer
445
views
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 ...
- 855
9
votes
2
answers
253
views
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 ...
- 2,087
5
votes
1
answer
508
views
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, ...
- 401
9
votes
2
answers
2k
views
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".
...
- 7,161
9
votes
2
answers
787
views
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 ...
- 7,161
11
votes
1
answer
216
views
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 ...
- 2,087
8
votes
1
answer
663
views
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 ...
- 193
6
votes
1
answer
118
views
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 ...
- 2,383
15
votes
2
answers
216
views
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 ...
- 4,889
10
votes
1
answer
114
views
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 ...
- 693
10
votes
1
answer
872
views
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:
...
- 511
8
votes
0
answers
148
views
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. ...
- 916
10
votes
1
answer
461
views
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:
...
- 511
14
votes
1
answer
341
views
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) ...
- 15.3k
21
votes
1
answer
280
views
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 ...
- 15.3k
12
votes
1
answer
1k
views
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 ...
- 341
14
votes
1
answer
303
views
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 ...
- 2,098
10
votes
1
answer
198
views
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....
- 2,098
11
votes
0
answers
355
views
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 ...
- 341
9
votes
1
answer
838
views
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 ...
