Atom Definition and 999 Threads

hi i asked myself, is it correct to use the ordinary partition function and cut it off at some value to describe the atom at some finite temperature? or is there a better way to do this calculation? and if i evaluate the partition function for let me say n=2. does this mean, that the...

I haven't posted any of my working for this as I only want to check my answer. Q. For a hydrogen atom with n=2, l=1, m=0 calculate <r^2> My answer = 0.75 * a^2 where a is the bhor radius. Am I right?

Homework Statement I need to calculate the probability distribution of 1s and 2p state of hydrogen atom in momentum and in coordinate representations. I have calculated the wave function in coordinate representation, and the dilemma is, do I simply do the Fourier transform for given wave...

Homework Statement Hi In my book, they do calculations on a 2-level atom. After some approximations, they reach the following equation for the coefficient for the first (lower) level: c_1(t)\approx c_1(0)e^{-i|\Omega|^2t/\delta} where Omega is the Rabi frequency and delta is the...

Homework Statement Define the quantum numbers required to specify the state of an electron in hydrogen. The spatial part of the wave-function describing a particular hydrogen atom has no angular dependence. Give the values of all the angular momentum quantum numbers for the electron...

it is obvious that the hamiltonian of an atom is time reversal invariant but how can an atom have non-zero magnetic moment?

Hydrogen Atom ---> Uncertainty Principle Hey guys, I'm having some trouble with this one. [PLAIN]http://img849.imageshack.us/img849/2039/physhw.jpg How do I get started?

If the proton in the nucleus of, say a hydrogen atom, exerts an attractive force on an electron that is in orbit, why doesn't the electron move towards the proton? And does this have anything to do with the electric force being the centripetal force?

I can think of two things. Stimulated Emission and Absorption. Would it be possible to do an experiment where you could control coniditions to allow just these two outomes? Thanks

Also, when an atom emits light when another particle hits it, why does one of the electrons move to the outer shell?

I'm dealing with this problem for an MCAT review: Following beta-emission by a neutral atom at rest, the respective linear momentums of the beta(-) particle and the resulting atom are shown below. (see attachment for message) It wasn't too difficult to see that an extra force is in play, and...

I have confused myself with this by reading a combination of Wikipedia, books and my QM notes and I'm afraid I need someone to untangle me please. Basically what I want to know is, what are the consequences of the Pauli exclusion principle for the ground state of the helium atom? Here's my...

Ok so my problem is I have absolutely no idea where to start. I have been able to figure out other problems but this I can't get my head around. I am unsure as to the equations I need to use for collisions and how to obtain the correct answer. Homework Statement A nuclear reactor (see...

Explain how an atom may have a permanent magnetic dipole moment? Many thanks...

Consider a hydrogen atom whose wave function is at t=0 is the following superposition of energy eigenfunctions nlm(r) (r, t=0) = *[2100(r) -3200(r) +322(r) What is the probability of finding the system in the ground state (100? in the state (200)? in the state (322)? In another energy...

Consider a hydrogen atom whose wave function is at t=0 is the following superposition of energy eigenfunctions \psinlm(r) \Psi(r, t=0) = \frac{1}{\sqrt{14}} *[2\psi100(r) -3\psi200(r) +\psi322(r) What is the probability of finding the system in the ground state (100? in the state (200)? in...

I had this https://www.physicsforums.com/showthread.php?p=3200140#post3200140", which I posted on PF. I got the answer, but then I started thinking more about it and have some theoretical questions. If you did have this particle of mass m in a box of length L, which you are trying to stop...

Homework Statement A K shell electron is ejected from a tungsten atom. The result of this is the emission of a characteristic x-ray proton. (The binding energy of the K shell in tungsten is 69.5keV. The binding energy of the L shell in a tungsten atoms is 10.5 keV). a) If the vacancy in the K...

The question is: Which species has exactly five pairs of electrons around the central atom? (A) ClF5 (B) SF4 (C) SF5– (D) XeF4 The answer is B. Can someone explain why? I'm not too good with these geometries that use the d-orbital.

Homework Statement Physicists use laser beams to create an "atom trap" in which atoms are confined within a spherical region of space with a diameter of about 1 mm. The scientists have been able to cool the atoms in an atom trap to a temperature of approximately 1 nK, which is extremely close...

Hi, I've some doubt about quanistic physicist (aren't homework I read this stuff as an hobby) , could you help me? 1)if the electrons of a gas, for example, emit energy only when they go down level, then to get the atomic spectrum should I first give energy and then wait until electrons go...

Non-relativistic QM. I have read in many places that the fourth power of the momentum operator (P^4) is not hermitian on the L=0 states of the Hydrigen atom. Indeed, I was able to pove this using Fnlm for the nlm state of hydrogen, computing <Fn00 | P^4 Fm00> and doing the integration by...

When acceleration reach to the point of speed of light, we know that space will collapse(3D) and time will slow down(relative) does this leads to the creation of atom? Will space collapse to a single point if time is take away? I view the space(3dimension) as a sphere in which time(relative)...

Hello, I just finished learning how to solve the Schrodinger equation for the H atom and a few things trouble me. 1) The relative particle, CoM particle treatment: From what I understand, we are solving this for the case where the nucleus is taken to have mass m1+m2 and the electron has mass...

Homework Statement A pion is a spin-0 particle with a negative unit charge. A neutron is a spin-1/2 particle with no charge. A proton is a spin-1/2 particle with positive unit charge. One can construct an unstable version of the hydrogen atom where the nucleus contains both a proton and a...

Homework Statement A 21 cm spectral line corresponds to the flipping of the electron in a hydrogen atom from having its spin parallel to the spin of the proton to having it anti-parallel. Find the internal magnetic field experienced by the electron in the hydrogen atom. Homework Equations...

Homework Statement In the Bohr atom, electrons move on classical circular orbits that have angular momenta lh/2pi, where l = 1, 2, . . .. Show that the radius of the first Bohr orbit is a0 and that the model predicts the correct energy spectrum. In fact the ground state of hydrogen...

1. Consider Bohr Hydrogen atom with counter-clockwise electron orbit in the xy plane with intial position r(0)=-a0y. The angular frequency of the orbit is w. Derive an expression for the position of electron at a later time t, r(t) in terms of a0 , w, t, x, and y. Homework Equations...

(1) Is there any equation to determine how many neutrons there should be to keep an atom stable? I don't mean mass - number of protons. I mean the equation that can determine an interval of neutrons based on atomic number only and the forces. (2)Why can't there be an hydrogen atom with 6...

I've heard that the hydrogen atom that we originally learn about in QM that deals with the Coulomb force is an incomplete description. I'm having trouble understanding all of these effects. When describing the electron energy of the real Hydrogen atom, how do things like the zeeman effect...

Hi everyone, How can I solve hydrogen atom with discrete nonlinear schrödinger equation? Could you help me with the mathematics of that, please?

Homework Statement "Relativistic effects are rather small in the hydrogen atom, but not so in higher-Z atoms. Estimate at what value of Z relativistic effects might alter energies by about a percent and whether it applies equally to all orbiting electrons or to some more than others. For this...

Homework Statement The nucleus of a lead atom has a charge of 82 protons a. what are the direction and magnitude of the electric field at 1.0x10^-10 m from the nucleus? Homework Equations E=Kq/r^2The Attempt at a Solution I did E= ((9 x10^9)(1.6X10^-19)^82)/ (1.0x10^-10)^2 but when I...

Hi. I'm a 3rd year undergraduate studying Applied Physics and I'm having some trouble with a problem concerning the Hydrogen Atom. This is my first post so please forgive the sloppy equations. Not really used to writing this stuff out without an equation editor handy! Anyway, the...

Homework Statement Fe3(Co)x, Fe is 33.26% by mass. Find the value of x. The Attempt at a Solution 167.5425 g / 0.3326 = x ( 58.9326 g) / 0.6628 x = 5.6... but the right answer given was x=12. question...

Hi! Today we discussed atomic physics in our class, and the following question came up: Consider an atom, and consider for example its three lowest energy states. Suppose these correspong to the energies E1,E2 and E3, respectively. Will it be possible for an electron in the lowest energy state...

On my notes, the lecturer left out some of the formulae as blanks which we were supposed to fill in as we went a long but I'm missing a few of them. The 1st one is: [PLAIN]http://img213.imageshack.us/img213/6627/screenshotdh.png I'm stuck here, I can't figure out what equation he's...

I'd like to consider a primordial black hole in the absence of Hawking radiation. When you consider the case of a primordial black hole with a Schwarzschild radius on the same order as the radius of a proton, I calculate its mass to be at around 6.75x10^11 Kg. If I then calculate the...

Hello Forum, This is my first post. There is some preamble, but the problem itself is straightforward enough, even though I cannot solve it. I'm trying to calculate the spin orbit matrix for an alkali metal atom at the centre of a complex of 12 noble gas...

Homework Statement Helium is used to fill a balloon of diameter 44 cm at 22 degrees C and 0.9 atm. The mass of a helium atom is 4.0026 u, the conversion factor from u to kg is 1.66 x 10^-27 kg/u, the conversion factor from atm to Pa is 1.013 X 10^5 Pa/atm, the universal gas constant is...

Homework Statement A neutron moving with a speed v makes a head-on collision with a hydrogen atom in ground state kept at rest. Find the minimum kinetic energy of the neutron, for which inelastic collision may take place. Mass of neutron = Mass of Hydrogen = 1.67 x 10-27kgThe Attempt at a...

if fuel coposition as follow : 75 wt% Tho2- 25 wt% uo2, were the U enrichment 19.5 w% ... how can i caculate the number density (Atoms/barn-cm) for the comopsition ?

Hydrogen Fusion = High energy? Where does the energy come from when a Hydrogen atom is fused? Is the energy stored in some part (proton, neutron, electron)? Thank you if someone can give me some idea about this. I guess it is about the strong nuclear force, but I'd like to know in a bit more...

The nucleus has positive charge, with negative electron shell(s) around it. The nucleus is located in the center of the electron shell. Electrical forces keep it there. Now what if we shine electromagnetic radiation (linearly polarised) onto an atom? With the E-field going "up", will the...

Hi, I'm trying to figure out the solution for the ground state of the hydrogen-atom, however it is not going well. As far as i know, you can supress the angular dependence, because the states of hydrogen (or at least some of them) are spherically harmonic. This way the schr. equation just...

Say for example we consider Helium. It has 2 neutrons and 2 protons. Based on this, and using Schodingers equation we can calculate the energy states of the various orbitals of Helium (using self consistent field approach or by completely solving the Schodingers equation using finite...

In the position representation, its true that we can use operators to represent the coulombic interaction between the proton and electron of a Hydrogen atom. I've never actually given any thought as to what the elements of such an operator would be (in matrix form of course). I know these...

Why can't every country make an 'Atom Bomb' ? Everyone knows that we require a fissionable material and an explosive. What else is required that is to be invented (rather discovered) by other countries? All comments are welcome.

Homework Statement An initial state is given: {\lvert {\psi(0)} \rangle} = \frac{1}{{\sqrt{3}}} \left( {\lvert {100} \rangle} + {\lvert {210} \rangle} + {\lvert {211} \rangle}\right) An L_z measurement is performed with outcome 0 at time t_0. What is the appropriate form for the ket...

Why their tracks after collision has an angle 90 degree? Any detail derive?