Questions tagged [quantum-chemistry]

For questions about quantum chemistry.

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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 ...
10
votes
0answers
89 views

Calculations of the charge transfer in GAMESS US

I'm trying to calculate the effective transfer integrals $J_{\text{eff}}$ from monomer A to monomer B within dimer AB by using GAMESS US: $$J_{\text{eff}}=\frac{J-S\cdot (e_1+e_2)/2}{1-S^2},$$ where $...
6
votes
0answers
52 views

Orbital space clustering

I am interested in how the orbital space of a system can be partitioned into clusters. I read reading 'Cluster many-body expansion: A many-body expansion of the electron correlation energy about a ...
6
votes
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68 views

Two-stage unbinding & binding energies with DFT

I'm trying to calculate the stability of the product of a coordinate bonding process of molecules A and B in the polarizable continuum solvent model (PCM, solvent set to water). I'm getting energies ...
5
votes
0answers
56 views

How to calculate energy gradient and Hessian with respect to only a few internal coordinates using Gaussian?

I would like to form the (numerical) gradient and the Hessian of the total electronic energy with respect only to a few internal coordinates (namely, the six intermolecular coordinates of a weakly ...