Questions tagged [transition-state]

For questions about determining/optimizing transitions states of chemical reactions

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5
votes
0answers
23 views

How do you perform parallelization of NEB-TS in ORCA?

I have tried running a NEB-TS calculation in orca with %pal nprocs 32, but I get an error saying ...
6
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1answer
105 views

Gaussian: Transition state convergence question

I am running a TS computation in Gaussian 16. It performs several steps. At the end of each there is a summary on whether Maximum Force, ...
6
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1answer
56 views

Vibrational frequency analysis for NEB result through Maestro

I have ran a Nudged Elastic Band (NEB) calculation using QuantumEspresso through Maestro to find the potential transition state. Within Maestro there is an option where you can select for NEB type ...
8
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0answers
58 views

Troubleshooting mechanistic calculation: Transition state energy and intermediate energy too close [closed]

I'm studying a mechanism of aromatic substitution of fluorine which proceeds via an intermediate. I'm searching for a transition state using a relaxed surface scan, then I optimize the TS and perform ...
11
votes
1answer
241 views

What are some of the biggest theoretical and computational challenges in Condensed Phase Chemistry?

What are some of the biggest open-questions / challenges in Condensed Phase theory and computation? What efforts are being done to answer them? I realize Condensed Phase chemistry is a huge field, but ...
9
votes
1answer
136 views

Energy decomposition analysis (EDA) at transition state

I am trying to understand the interaction between the nucleophile and the substrate for some SN2 reactions (e.g. $\ce{I- +CH3Cl->CH3I + Cl-}$) at the transition states. Now, it seems that EDA would ...
8
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1answer
90 views

Isotopes in Reaction Kinetics by Transition State Theory

Can kinetic isotope effects be handled in density functional theory level calculations? My intuition says that in the context of molecular dynamics simulations that they can be, but can transition ...
10
votes
1answer
102 views

Correcting thermodynamic data for concentration, what concentration is best to use?

In computational chemistry when using transition state theory we often use standard states for all involved structures. However, sometimes people argue that it should be corrected for concentration (...
17
votes
1answer
119 views

Benchmark transition state geometries in condensed phases

I'm seeking references/benchmarks for transition state geometries of reactions in condensed phases like crystals, zeolites, or surfaces. Basically the system just needs to be considered big, yet ...
13
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1answer
144 views

TS-search with explicit solvent

I'm looking for an advice how the best to set up the system and optimize a transition state with explicit solvent. I believe that solvent molecules are participating in the reaction by specific ...