Question related to charge calculation

[dua.harkishan@yahoo.com]

I am trying to calculate Fukui Function for periodic system using quantumATK inspired from the work J. Phys. Chem. A 2020, 124, 2826−2833 (using VASP code). As in the mentioned paper they have generated the CHGCAR file (the total charge density multiplied by the volume) for different fractional charges as well as neutral charges. Now, I want to generate the same using ATK. I have generated electron density but I am not understanding how to make this file similar as that of CHGCAR file and also I am not understanding what are the different values in electron density file represents. Another point is that how to give fractional charges during calculation.

[Anders Blom]

It's not a problem to give a fractional charge, there is a "charge" argument to the LCAOCalculator (https://docs.quantumatk.com/manual/Types/LCAOCalculator/LCAOCalculator.html) which can take any floating number.

As for computing the Fukui charges, why not just implement it the function in Python, using the data already available in the object returned from the QuantumATK calculation? The ElectronDensity holds the charge density in a volume grid which can be subtracted from the neutral case and manipulated easily in Python.