Higher Order J Hopping

In this part of the manual we will present the settings required in QuantumPatch to generate the LightForge input allowing for superexchange hops over higher order states and to allow for hops into higher order states with further virtual intramolecular postrelaxation using phononic coupling. The processes are illustrated in the following two images.

SuperExchange over a virtual middle molecule hop IntraMolecular virtual relaxation over a higher order state

The following steps have to be carried out:

  • A QuantumPatch "Calculate Js" calculation including Higher Order Js
  • An IntraOverlap Calculation with the same basis used in the QP step.
  • An ExtendJs calculation with input from the prior two WaNos

The rough workflow is shown here:

While everything could in theory be run in a single workflow, it is not advised, as each of the steps requires a large amount of computational time.

QuantumPatch Dimer Calculations

Do a standard uncharged equilibration QuantumPatch calculation as explained in the previous tutorial. Set the number of higher order Js to the number of higher order hops you would like to consider. Usually a number higher than 7 will only yield diminishing returns at higher calculation costs. Keep the file Analysis.zip and the structure.cml file.

Also take note of the used basis and functional.

IntraOverlap WaNo

The IntraMolecular Overlap WaNo IntraOverlap calculates the averaged matrix elements for a vibronically mediated transition between states LUMO+N and LUMO or HOMO-N and HOMO. An average is taken over the vibrational modes. The WaNo is shown here:

The vibronic overlap integrals will be calculated for each unique molecule if the molecule ids settings is left at its default: . If only a specific molecule type is requested, specify one or multiple ids.

Set the Turbomole settings to their appropiate values of QuantumPatch, i.e. Basis and Functional have to match. The WaNo runs on one Node only. Allocate as much memory and cores available on one node as possible. Afterwards save IntraOverlapAnalysis.zip.

ExtendJs WaNo

Provide all calculated Analysis.zip files and the IntraOverlapAnalysis.zip files and the morphology. For each material in structure.cml, a IntraOverlap calculation has to be run. This can be split in multiple calculations or carried out in a single one, as required. Theoretically the QuantumPatch Dimer calculations can also be split into multiple calculations, but we advise against that to keep a better overview.

Results

Afterwards the Analysis/files_for_kmc folder will have additional files conducting J analysis. All files have the same format: "COM_Distance J[eV]" The files are as follows:

  • normaljs_HOMO.dat and normaljs_LUMO.dat containing the Js prior to the higher order correction
  • intrajs_HOMO.dat and intrajs_LUMO.dat containing the Js corrected using only the virtual vibronic intramolecular relaxation.
  • superexjs_HOMO.dat and superexjs_LUMO.dat containing the Js corrected using the factors of three molecule hops
  • superex_and_intra_js_HOMO.dat and superex_and_intra_js_LUMO.dat containing the Js corrected using both virtual intramolecular relaxation and superexchange.

The following graphs show the impact of the intramolecular relaxation and superexchange in the case of TBPi HOMO transfers.

Only effect of intramolecular relaxation considered, Black: NormalJs Effect of both intramolecular relaxation and superexchange considered, Black: NormalJs

As can be seen in the plots, intramolecular relaxation increases the absolute value of the Js, while superexchange especially provides transfers between hopping sites further away from each other.

 

 

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