Dft Definition and 112 Threads

Homework Statement I have been asked to calculate the bulk modulus for a carbon dioxide solid from data I have calculated. I have made a quick plot of unit cell size vs pressure (sorry for no labels, unit cell is Y axis as square angstroms, and pressure is in GPa), which looks ok...

Homework Statement Given a discrete Fourier transform, create a fast Fourier transform. Homework Equations The DFT: X_k = \sum_{n=0}^{N-1} x_n e^{-\frac{2 \pi i}{N} k n} \quad \quad k = 0, \dots, N-1 The Attempt at a Solution I've heard about split-radix and Cooley-Tukey, but I'm...

any CASTEP users or DFT planewave-pseudopotential method users out there? how do I ensure that the basis set is adequate? I'm performing calculations with a rather large unit cell ( orthorhombic, 8 atoms/cell) of a compound AB. Can I justify my choice of energy-cutoff by testing...

What is the justification behind tight-binding, nearly free electron drude model, to assume electrons as non-interacting? Because it is clearly not the case when considering coloumbic interactions, why can these models do this? Coloumbic interactions are strong so I wouldn't consider them to be...

Hi, i can't understan clearly the Exchange-correlation term that appears in the develop of DFT. The only thing i know is that the first comes from the pauli exclusion principle, and the second from the quantum part of the coulomb interaction between electrons. Am i right?? but i wan't to go...

hey guys - i can't seem to find find this statement anywhere - but it makes sense to me - could someone please verify. When you find the DFT of a signal say: x[0]=2, x[1]=4, x[2]=6, x[3]=8 - you will get four discrete points in frequency (per period) now if you zero pad the time signal such...

DFT - can't evaluate components in -negative time! hey guys - if you look at the definition/equation of discrete Fourier transform, you will see that we can only evaluat values from n=0 to N (see http://en.wikipedia.org/wiki/Discrete_Fourier_transform, to view the equation)...but what have we...

"Simple" DFT software Hi, is anybody aware of a "ligthweight" DFT software to be used as a tutorial (say for undergraduate students, etc.), so very simple to configure, use, and visualize results? Installation on a Windows platform would be the best... thanks Fabio

Dear all: I want to calculate the C-C bond energy of diamond and the dangling bond energy on diamond surface by DFT. How can I do? Can you tell me ? Thanks a lot! H. L. Yu :confused:

Hi All! I was wondering what are my chances in applying for a PhD in physics... I have a master's degree, I was involved in some computational stuff in Density Functional Theory, I also graduated in this field. My problem is, that I have not been some eager-beaver guy with my studies...

I'm considering the 12 –point sequence x[n] which is defined as x[n] = {1, 2, 3, 4, 5, 6, 6, 5, 4, 3, 2, 1}. I'd like to use Matlab to find the DFT (X[k] of x[n]) and DTFT (X(e^jw) of x[n]). I realize that the DFT is sampled version of DTFT, and I want to show this graphically using...

Someone helps me ! I'm looking for where I can download free e-print about Tensor Calculus and Density Functional Theory . I want to teach myself. Thank you very much .