Density functional theory Definition and 24 Threads

I have a question about how DFT (density functional theory) handles degenerate states. The Hamiltonian in DFT is a functional of the electron density defined via ##n(\mathbf{r})=\sum^N_{k=1}|\psi_k(\mathbf{r})|^2##. However, say I have a pair of degenerate states. Then any linear combination of...

I've found channels like this very helpful in the course of my PhD program. I use DFT to study various materials; primarily semiconductors for technological applications. I'm excited to now be a part of PF and I look forward to being a part of the discussion.

I'm reading through Hohenberg's seminal paper titled: "Inhomogeneous Electron Gas" that help lay the foundation for what we know of as Density Functional Theory (DFT) by proving the existence of a universal functional that exactly matches the ground-state energy of a system with a given...

In density functional theory (DFT), electron density is a central quantity. Because of this, we want to calculate electron - nuclei potential energy as functional on electron density. If we know how potential energy varies across space, we can calculate this functional with plugging particular...

hello all i am a new member on Physics Forum i am a last year master student in fundamental physics ( again ) and also have done a master in condense mater and nano-science i worked on noble solid /amorphous interface in my first master internship ( DFT and ab initio molecular dynamic using...

Hi, I have a blog oriented on computational physics: https://compphys.go.ro For many posts I have a GitHub project. Lately I started some DFT oriented ones, the latest being a DFT (with plane waves basis) project for a 'quantum dot'. Currently I started working on a project that will use the...

Hi guys, I'm trying to use the CASTEP software for dft calculations. I have plenty of documentation on how to use it once it's all up and running, however I don't know how to get to that point :/ I'm not the best with linux but I've manually installed programs before through tarballs but here...

I'm starting out on DFT right now. I'm an experimental Physics student, so I'm not very familiar with theories. Can you recommend any good textbooks or resources that I can utilize for my study?? Thanks in advance.

Hi there, Apologize in advance if this is not the correct place to post my query. I've been googling didn't get it or maybe my input search parameter is not sufficient or irrelevant. I am recently doing my graduate in physics and my inclination towards computational physics makes me to do my...

Homework Statement A quarter disc of radius 3 cm lies in the first quadrant. The areal density is (1.2 g/cm3)x + (0.7 g/cm3)y. Determine the mass of this object. Homework Equations The Attempt at a Solution For my bounds: x: 0 to 3 y: 0 to Sqrt[3 - x^2] When I took this integral I got...

When studying defects using plane-wave basis density functional theory, it is necessary to ensure that the size of the supercell in which the defect is located is large enough to ensure that there is no interaction between the defect in question, and the periodically repeated defects that are a...

I am referring to perturbation expansion of density functional Kohn Sham energy expression in Phys. Rev. A 52, 1096. In equation (92) the variational form of the second order energy is listed, but I cannot seem to work out the last 3 terms involving XC energy and density. Particularly, the...

Homework Statement I am running CASTEP DFT software to simulate pristine graphene, and am unsuccessful in obtaining the trademark zero band gap at the k-point as reported in numerous papers to date. Any assistance would be greatly appreciated as the subject is very new but I am keen to push...

When density functional theory is used to simulate a molecule adsorbed on a surface, it turns out that due to their interaction, a fraction of an electron is transferred from the surface to the molecule or vice versa. These interactions are normally categorised in interactions involving...

Dear PF, I'm reading a book on DFT, and it says that only ground-state wave function is a unique functional of the ground-state density, n(r). However, if in DFT the potential, v(r), is a unique functional of n(r), then shouldn't all wave functions be functionals of n(r), because you can...

Hi all, A professor asked me to do something, but I'm not quite sure what he means -- He asked me to use Density Functional Theory (DFT) calculations of the band structure of a certain crystalline metal and adjust the matrix elements of a Tight Binding (TB) model to make a "minimal" TB model...

I am a new user for Quantum Espresso(QE). Recently I have installed Quantum Espresso in my system. Now i am struggling to give input file in QE. How to generate input file in QE?

I just finished my undergrad in Chem Eng and am very interested in energy field ( I was thinking of doing something with battery and storage systems as it is closest to my field). I was recently offered a masters in MSE for possibly working on battery materials using Density Functional Theory...

Hi,all Is there someone's research related to DFT? I'm an undergraduate trying to get into it. I hope I could get some help hear if I have any question about that! Thanks a lot,Euphemia

Im trying to calculate the ground state energy of Helium using a density functional theory approach combined with the local density approximation. So far I have set up universal functionals and I mainly need help with the actual algorithm the evaluation of the Hartree energy functional.

Hi, I want to start reading about Density Functional Theory and get through some of its approaches. I have a vey weak back ground of solid state physics. Please guide me what is the best resource to start reading. Regards

I try to learn DFT by myself(Kohn-Sham Equations), but the concept is still not so clear for me. So far, if I start with assuming any density, and then I would be able to find V(KS) Then I use this hamiltonian and solve for a wave function. And I use this wave function to find another...

Hi, i am looking for papers, books, etc, related with the Density functional theory, and Kohn Sham equations, i appreciate any help. Thanks. :rolleyes:

I'm trying to learn density functional theory by myself, but I'm a bit confused as to how to use it. Is the following methodology correct (I think it'd take forever to use LaTex to write the equations, so I have a link to small webpage that already has the equations laid out and numbered)...