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Questions tagged [excited-states]

Refers to an atom or molecule with an electronic configuration in a higher than normal energy state than it's ground-state. The excited-state may relax radiatively or non-radiatively.

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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 ...
ProfM's user avatar
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21 votes
1 answer
270 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 ...
Jack's user avatar
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16 votes
3 answers
3k views

Can you estimate the electronic excited state lifetime of a molecule?

I want to estimate the lifetime of an electronic excited state. Lets assume there is only radiative coupling via spontaneous emission from this state to the ground state. I can optimize the excited ...
Hans Wurst's user avatar
16 votes
2 answers
2k views

How to understand the spin of exciton?

In very recent years, exciton physics has been intensively explored as the emergence of 2D materials. Exciton is a bound electron-hole pair and is bosonic, namely hosting an integer spin. My first ...
Jack's user avatar
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16 votes
1 answer
311 views

What methods can be used to calculate excited-states in molecular crystals?

In periodic systems plane-wave basis functions are often used. In a previous question on this site it was questioned if plane-wave basis-sets are reliable for modeling adsorption-processes The ...
Cody Aldaz's user avatar
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14 votes
1 answer
306 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) ...
Jack's user avatar
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13 votes
1 answer
163 views

Photoemission Spectra of Solids

I know that in non-periodic codes such as Gaussian the fluorescence spectra of molecule can be calculated in the following manner. Relax geometry TD-DFT to find excited state Relax excited state ...
Tristan Maxson's user avatar
13 votes
1 answer
133 views

What progress has been made in modelling photocatalytic reactions on semiconductor surfaces?

For example, are there any methods to allow for modeling of photo-oxidation or photo-reduction of a compound on a semiconductor surface? It appears there has been a lot of work on the bulk properties ...
Tristan Maxson's user avatar
13 votes
0 answers
302 views

Calculating Core-Level Binding Energies (XPS) using DFT

I'm pretty new to DFT calculations but I'm trying to learn how to do X-ray photoelectron spectroscopy (XPS) calculations, particularly for open-shell molecular systems in common non-periodic DFT codes....
Ademola Soyemi's user avatar
11 votes
2 answers
1k views

Calculating the excited state dipole moment

I am trying to calculate the dipole moment of an excited state, using "Gaussian" software. My input commands were: ...
aerospace's user avatar
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10 votes
2 answers
254 views

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 ...
TheSimpliFire's user avatar
9 votes
2 answers
728 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 ...
S R Maiti's user avatar
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9 votes
2 answers
213 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 ...
Jack's user avatar
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9 votes
1 answer
228 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 ...
Hans Wurst's user avatar
8 votes
1 answer
335 views

Optimization and vibrational analysis of excited state CO using GAMESS

I am facing some problems in performing HESSIAN analysis on excited states of molecules: I am testing it out with CO. My input file to GAMESS is pasted below. Could ...
madhusudana's user avatar
8 votes
1 answer
164 views

Excited states using ORMAS flag in GAMESS

I am trying to calculate the excited states using single reference CISD on $\ce{CH3OH},$ using ORMAS' CI-X option in GAMESS. As a test example I am using the $\ce{CH3OH}$ that has 2 core, 7 occ. ...
Debopriyo Chaudhuri's user avatar
7 votes
1 answer
2k views

How can I calculate the energy gap between the singlet and triplet state using ORCA?

I came across this publication that calculates the $S_1$ - $T_1$ energy gap using TDDFT as implemented in Gaussian. I would like to do the same using ORCA. Im extremely new to ORCA and local orbital ...
Fang Leu's user avatar
6 votes
2 answers
214 views

Closed-form expression for excitation energies, given the exact XC functional

In an answer to my question regarding the theoretical rigour in computing excitation energies using only the Kohn-Sham orbital energies, the rigour turned out to be nonexistent. After looking this ...
Kanghun Kim's user avatar
6 votes
2 answers
235 views

Excited state normal mode frequency doesn't match for NH3

I am trying to optimize the geometry of excited state NH3 and get the corresponding normal modes for excited states. I am trying to get the frequencies as mentioned in this reference. They claim to ...
madhusudana's user avatar
6 votes
1 answer
108 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 ...
Roman's user avatar
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6 votes
0 answers
44 views

What is the lifetime of propane at standard conditions transitioning from an excited rotational state back to ground state? [closed]

I am a retired microwave engineer (88 yrs old) and have not had the opportunity to study or learn anything about quantum physics. I designed and built radars for the military. We found a claim that ...
ghawk's user avatar
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6 votes
0 answers
98 views

Transition dipole moment derivative TURBOMOLE [closed]

I am trying to calculate transition dipole moment derivatives using Turbomole 7.3. For some reason, and although I think I included the neccessary keywords to perform such a calculation, they are not ...
Paul Logan's user avatar
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,...
S R Maiti's user avatar
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5 votes
1 answer
283 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 ...
Laura's user avatar
  • 1,267
5 votes
1 answer
229 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 ...
HCSthe2nd's user avatar
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5 votes
1 answer
155 views

Question on generalised Kohn-Sham "band gap"

It is often said that the optical band gap, i.e. the first excitation energy, of a species is exactly equal to the difference between the (Kohn-Sham) HOMO and LUMO. This would mean that the state of ...
Kanghun Kim's user avatar
5 votes
1 answer
170 views

Calculation of S1 energy in Gaussian

I am trying to calculate the energy of the S1 state with UDFT in Gaussian software. I understand that, generally, one should manipulate the charge and spin multiplicity to manually change the ...
Laura's user avatar
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5 votes
1 answer
57 views

A matrix form used in the Quantum Annealer Eigensolver (QAE)

In the paper "Computing molecular excited states on a D‑Wave quantum annealer", PySCF is employed to compute the TDA matrix. Then a few of the lowest eigenvalues and eigenvectors of a TDA ...
Hadeel Moustafa's user avatar
5 votes
0 answers
27 views

Core-valence separation (CVS) keyword in MRCC program [closed]

I am interested in using the CVS option in CI calculations to get core-excited states. I tried to use the MRCC program which possesses this option according to the manual (cvs=...). I performed some ...
EvGeniy's user avatar
  • 371
4 votes
1 answer
787 views

Optimise S1 geometry with CASSCF in ORCA

I'm trying to optimise the excited state of benzene using ORCA 5.0.1 software. I've already optimised the $S_0$ geometry with CAS-SCF[6,5] with the following input file ...
Andrea Pellegrini's user avatar
4 votes
1 answer
81 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 ...
WALOWLA's user avatar
  • 41
4 votes
1 answer
297 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 ...
Laura's user avatar
  • 1,267
4 votes
0 answers
23 views

How to evaluate excited state MO coefficients using Dalton Pacakge?

I need the excited state (T1) wavefunction associated with my benzene molecule, but even after trying multiple times using multiple input formats, I am not able to find the correct input to evaluate ...
compcal's user avatar
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4 votes
0 answers
265 views

How to plot emission spectrum using gaussian? [closed]

I'm trying to learn how to plot emission spectrum for my system, but, as an initial test case, I'm trying to do this for methane. I calculated the optimized geometry of the ground state, then I ...
diamond999's user avatar
4 votes
0 answers
74 views

Do the orbital energies of ground-state Dyson orbitals exactly capture arbitrary excitation energies and/or ionisation potentials/electron affinities? [closed]

According to an answer to my question on whether the Kohn-Sham orbital energies theoretically exactly capture arbitrary ionisation potentials and/or excitation energies, the answer is no for both ...
Kanghun Kim's user avatar
3 votes
1 answer
239 views

Singlet excited state optimization gaussian issue

I hope someone here can help me with some TD-DFT calculations. I am trying to calculate the excited state optimised structures and energies of some Germanium compounds. Firstly, I run a TD calculation ...
F Leon's user avatar
  • 31
3 votes
1 answer
180 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 ...
Hadeel Moustafa's user avatar
3 votes
1 answer
164 views

Is this method of obtaining only the exact "other" densities, and no other properties w.l.o.g, correct?

In Kohn-Sham DFT, the exact density of the ground-state wavefunction is given by summing the squares of the filled K-S orbitals. Suppose now that one only needs the exact density (and nothing else w.l....
Kanghun Kim's user avatar
3 votes
1 answer
105 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, ...
farmaceut's user avatar
3 votes
1 answer
98 views

Excited states of Lithium in MOLPRO

I am trying to run an exciation energy calculation for a lithium atom. Is there a way to force the initial HF calculation to follow a specific excited state configuration, i.e. to skip or leave some ...
ZHIBO LIU's user avatar
3 votes
0 answers
32 views

Is this method of obtaining only the exact "first excited state" density correct, under select conditions that makes it mathematically non-ambiguous? [closed]

(For context, see my other question here; this has been disproven (albeit contestedly), and is not even well-defined in the first place, so I'm going to ask a slightly different (and well-defined) ...
Kanghun Kim's user avatar
3 votes
0 answers
519 views

STEOM-DLPNO-CCSD [closed]

I have to calculate the S1 - T1 energy gap using coupled cluster (STEOM-DLPNO-CCSD) in ORCA. The output file contains only singlet energies. IROOT=... (no notation singlet or triplet). I tried adding &...
Darya Tarakanovskaya's user avatar
2 votes
1 answer
261 views

'The combination of multiplicity electrons is impossible' in Gaussian

I am trying to calculate the energies of the S1 and T1 states of a molecule with UDFT using Gaussian. For the T1 state, I can successfully use the following input file: ...
Laura's user avatar
  • 1,267
2 votes
1 answer
212 views

Calculating vertical excitation energies at the DLPNO-STEOM-CCSD Theory level

I want to calculate the vertical excitation energy using the DLPNO-STEOM-CCSD method, on molecules previously optimized using TD-DFT. the parameters being used are as follows: ...
Madeleine Fisher's user avatar