Density of states Definition and 130 Threads

Homework Statement I am trying to understand how we go about calculating the density of states in situations where the available quantum states are continuous, e.g. electrons in a white dwarf. I am happy to accept the uncertainty relation (we learned to derive it as the product of the...

Hi guys In some articles I've read, they all mention that the (local) density of states is related to the retarded Greens function for a non-interacting system by -(1/π)Im[G(r,ω)] = LDOS(r,ω), i.e. the imaginary part of the Greens function. The above relation holds because in k-space the...

Hi guys I have an analytical expression f(x) for my density of states, and I have plottet this. Now, I also have a complete list of my Hamiltonians eigenvalues. When I make a histogram of these eigenvalues, I thought that I should get an exact (non-continuous) copy of my plot of f(x). They...

Hi guys I found this on Google Books...

Homework Statement Consider an isolated system consisting of a large number N of very weakly interacting localized particles of spin 1/2. Each particle has a magnetic moment \mu which can point either parallel or antiparallel to an applied field H. The energy E of the system is then E =...

i have an equation for the density of states that depends on 1/(sqrt E). i have lots of coefficients to this [Vm^{3/2} w_c ] / [2 sqrt {2} pi^2 hbar^2] do these coefficients represent the degeneracy of the desity of states?

Hi. I'm studying the transition rates between a state a and a state b in the continuos level. In the book "Physics of atoms and molecules" by Bransden and Joachain it is said: We have to calculate the density of final states. To do this let the volume V be a cube of side L. We can impose...

Hi, I am trying to find an expression for the density of states of free two-dimensional electrons, as a function of energy, and I am really struggling. I get that what I am looking for is the number of states per unit area of k-space per unit energy, and in general (3D), this is expressed as...

Hi, I have a question about statistical mechanics. How do you calculate the density of states for phonons and electrons in a d-dimensional system (at fixed chemical potential) and when the dispersion relation for the electrons is E(p)=A |p|^g and for the phonons is w=v|p| To get the...

Hello, is it possible to roughly estimate the density of states just looking at the band structure E(k) of a solid? Thanks

Hi, I would like to know what local density of states (LDOS) is and what differences it has with projected density of states? Also, when we choose a smaller isolevel we have a denser local densities of states, why? Regrds,

Dear all, I really need help. My question: How do i project the density of states onto orbitals of atoms? this is to do a charge analysis. Can anyone provide me with an eqn or refer me to any relevant text or paper. Greatly apprieciate your help. Thanks nisha

calculate the density of states and average energy for an elctron gas in 1d,2d and 3d I know the number of states is N= \int_{0}^{infinity} g(e)f(e) de and E = \int_{0}^{infinity} g(e)ef(e) de and g(e) =dN/de

Hello, folks. Q: How can one measure the density of states of a semiconductor and a conductor? I would imagine you want to measure the charge carrier density and then you can calculate the density of states. If so, what observable(s) can yield the charge carrier density? How can you...

Homework Statement We study a one dimensional metal with length L at 0 K, and ignore the electron spin. Assume that the electrons do not interact with each other. The electron states are given by \psi(x) = \frac{1}{\sqrt{L}}exp(ikx), \psi(x) = \psi(x + L) \psi(x) = \psi(x + L) What is the...

Homework Statement We study a one dimensional metal with length L at 0 K, and ignore the electron spin. Assume that the electrons do not interact with each other. The electron states are given by \psi(x) = \frac{1}{\sqrt{L}}exp(ikx), \psi(x) = \psi(x + L) What is the density of...

"the density of states (DOS) of a system describes the number of states at each energy level that are available to be occupied. " But I thought there can't be more than 1 electron in a state? How does DoS have any meaning when dealing with eleectrons?

So we all know, or can look up Fermi's golden rule to be something like: \sigma\left(E\right) \propto \rho\left(E\right) |\langle \psi_i | \mu | \psi_f\left(E\right) \rangle|^2 Sigma is the cross section (or can be the transition rate as well), rho is the density of states of the final state...

[SOLVED] density of states for a Bose gas Homework Statement My book (Kittel) says that the density of states of an ideal Bose gas is:D(\epsilon) = V/4\pi^2 \left(2M/\hbar^2 \right)^{3/2} \epsilon^{1/2} I do not understand why the density of states is not identically infinity since the point...

condensed matter--integral over density of states Homework Statement http://online.physics.uiuc.edu/courses/phys460/fall06/handouts/460-lect12.pdf Could someone explain to me why the first equation on slide 22 is true? Homework Equations The Attempt at a Solution

Hi All Im just wondering if there is an easy way to determine the density of states for a molecule such as CO2. I am interested in transitions at IR wavelengths so I'm wondering if there is an 'easy' way to get at the vibrational modes only to chuck into something like the Maxwell-Boltzmann...

Hi, I have a question regarding the contribution of some molecular orbitals (e.g HOMO, LUMO) to the total density of states of a two-probe system. How exactly are the contributions of the MO ( that look similar to the DOS plots ) calculated, do they have something to do with the local...

If an infinite discrete sum is calculated via integrating over a density of states factor, is this integral an approximation to the discrete sum? i.e the discrete sums could be partition functions or Debye solids.

Hi! I want to calculate the density of states in the 3D, free electron gas, but I don't know how to do this. Can somebody help me? Thanks!

Although I have some major conceptual problems with the Fermi gas as treated in my solid state physics notes (see this thread: https://www.physicsforums.com/showthread.php?t=161222, I have attempted to solve this homework problem in an analogous manner to the solution for the 3D Fermi gas given...

Density of states?? According to C. Kittel the density of states is the "number of orbitals per unit energy range". Alright, that's fine, but what exactly does this mean? I can understand the calculations, finding the totalt number of states by considering the fermi sphere and the volume of a...

upon recent studies of the Density of states and Specific heat capacities, I've found the Einstien and Debye Models to be very helpful, Debye being the more accurate of the two models at low temperatures as it takes into account the low frequency modes. However, the realistic density of states...

what is the essentail difference between local density of states and density of state? It is very difficult to figure it out

The Density of States diagram gives gaps sometime. As I know, if the band is filled up to the gap, then the material is an insulator. However, it seems to me, that superconductors also open a gap in their density of states diagram, as BCS theory says. If my understanding is correct, I am a...

Dear all: I am frustrated in the concept of the PDOS, may someone be kind to refer me to the origin of this concept? Thanks. Regards