Atom Definition and 999 Threads

Homework Statement In an examination of a certain element using the Debye-Scherrer technique the following diffraction angles (in degrees) were noted: 45.26/65.92/83.56/100.6/118.68/140.88 Radiation λ=0.1540 nm was used. Obtain two estimates of the atomic diameter of the element in...

Homework Statement By substituting the wave function \psi (x) = Ax{e^{ - bx}} into the Schoedinger equation for a 1-D atom, show that a solution can be obtained for b = 1/{a_0}, where {a_0} is the Bohr radius. Homework Equations - \frac{{{\hbar ^2}}}{{2m}}\frac{{{d^2}\psi...

Homework Statement Given the numerical value of a0= 5.3X10^11m in the Bohr hydrogen atom, find the radius of the first five orbitals as well as the radius for n=100. Homework Equations Rn=a0 x n^2 The Attempt at a Solution Could it be as simple as typing in for the third orbital...

Dear, I am reading a paper on Bose Einstein condensate and an atom laser. I have two questions which are bothering me for a time. - When you are going to make do all the atoms start with the same the Broglie wavelenghts or do they start with different wavelenghts due to different...

the electrical activity of an atom is the same electricity of a light bulb?

Homework Statement Using Hund's rule, find the fundamental term of an atom whose last incomplete subshell contains 3 electrons d. Do the same with 4 electrons p. Homework Equations The 3 Hund's rules. The Attempt at a Solution By fundamental term I'm guessing they mean the...

Homework Statement a group of atoms are confined in a point like volume in a laser based atom trap, the laser light causes each atom to emit 1.0 x 10^6 photons of wavelength 780 nm every second. the sensor has area of 1 cubic centimeter and measure the light intensity emanating from the trap...

Is it possible to replace one of the electrons in a heavy atom like uranium with an Antiproton and form a stable atom?

how spinor vector envolves in describing the atom

Assume the universe consists of a single photon, a single atom of hydrogen and a spherical detector (like an encompassing shell) with a semi-infinite radius. The photon gets "absorbed" by the hydrogen atom. Moments after the photon is emitted. My question is the following: from the time...

How do you calculate the surface atom density of an fcc(111) surface expressed in terms of a? I've managed to do it for fcc(100) and fcc(110), but I can't seem to figure it out for fcc(111). Any help would be greatly appreciated!

Eisberg and Resnick says that the condition for stability of the atom is: k Ze2/r2=mv2/r What I fail to understand is why the Z isn't square too. I mean surely you have Z electrons interacting with Z protons which which would surely give q1q2=(Ze)(-Ze)=-Z2e2? What am I missing?

This ought to be simple, I think. But I haven't found a consistent way to think about things yet. Is it as simple as adding up all the spins of the elementary particles in the particle and checking whether the total has inter or half-integer spin? Homework Statement State whether the...

as far as i know it takes certain amount of energy for an electron to change orbit now what i am wondering is why the energy required for an electron to change orbit doesn't change when close to let's say another positively(or)negatively charged atom thank you for your time and sorry for the...

Is the ionization energy of Francium to high to be achieved with just one photon? And another quick question, how hot must the light-emitter get before it begins to emit x-rays, and then how hot for gamma rays?

Why can't an electron have a even lower energy level in atom and be closer to the nuclei? (as the next step is to fuse with one of the protons and make neutron.. )

I am looking for a fairly simplistic answer to why different "shells" in atoms can only hold a specific number of electrons. There is so much based on valence electrons and how many electrons make a full shell but, do we know why atoms "seek" a full outer shell? It seems like there should be a...

Hi I am reading about the force of a coherent EM-beam acting upon an atom, and I have a question in this regard. It is regarding the explanation on page 150 of this book, starting from "The geometric approximation of atom optics is valid when"...

I almost have the answer, I'm sure there's just a minor flaw in my reasoning. Here it goes: We're given that the angular momentum of the atom is integer multiples of h-bar (n\hbar) (integer depending on the orbit). Now the centripetal force is given by F = \frac{mv^2}{r} = \frac{p^2}{mr} =...

Hi In the following paper (on page 5) is the standard derivation of the force acting on an atom, whose center-of-mass motion is described classically. What I don't understand is the step taken from (5) to (6). The QM-version of the force is defined using Heisenbergs Equation of Motion (so...

I know that when a photon strikes an atom, it excites an electron, which then will re-emit the photon when it returns to normal. But what is actually happening here? Is it really as simple as that, or is there something more fundamental going on here, like how nuclei are bound together using...

What object would represent the size of a grain of salt at this scale? Would it be bigger than Earth?

Ok i don't know anything about quantum physsics but when i was reading about it( for the sake of learning new stuff) i had this question :- Does the attraction between protons and electron play a role in determining where the electron probability is maximum at? I was seeing the graph of...

If a a 1s hydrogen atom is placed in a B field, how many energy states will it split into?

If I may, I would like to give this question another try, especially if guys with some cabala in QFT can address it. Is it possible to show in the relativistic quantum theory, that the hydrogen atom is stable? (Electron will not fall onto the proton)? I explain. In the non-relativistic...

helo can someone tell me where I can find detailed explanation about normalization and orthogonal properties of the radial functions since the books I've been reading do not explain enough, I thought Laguerre associated polynomials resolved the problem directly but this is not the case, the...

Homework Statement Consider the following energy levels of a hypothetical atom. E4 -1.0 10-19 J E3 -5.0 10-19 J E2 -10 10-19 J E1 -15 10-19 J (a) What is the wavelength of the photon needed to excite an electron from E1 to E4...

About the atomic radius, as a starter it was mentioned (and correct me if am wrong) that: Rcation < Ratom< Ranion (And we'll know the size of the atom based on these) Then it was mentioned that: Radius of atom of a certain element increase if we walk straight downwards along a column in the...

How big would the nucleus be? A grain of sand (0.1cm diameter) A marble (1cm diameter) It's a grain of sand right(?); since the relationship between the diameter of an atom and its nucleus is 100,000 to 1. 150/0.001= 150,000

Homework Statement I have a problem on my assignment in which I am required to find the specific heat of a two atom basis (diatomic) using the Debye model. My problem is coming up with the density of states for a diatomic setup in 1D. Homework Equations Density of state...

Homework Statement i) Write down an expression for the LJ cohesive energy of a molecule consisting of four atoms lying on the corners of a square of side a. ii) Deduce the equilibrium value of the nearest-neighbour separation, a, assuming the molecule retains its square shape iii) What...

Hi, I am trying to understand how do cluster of niobium atoms behave when I apply force to compress/stretch them. Niobium has a cubic lattice structure, 8 atoms on each corner and 1 in the center. So my question is let's say I have 2 of these cubes connected, and composed of 14 atoms. In...

Hi everyone! So we're learning about the Hydrogen atom in QM and I'm having trouble reconciling something in my head. We're looking at potentials that are only radius dependent, like the Coulomb potential. Now, I know the math. I see that we assume the wave function can be separated into the...

Homework Statement For the (100), (110), and (111) planes of a Silicon crystal sketch the placement of atoms on the plane and determine the atom density (atoms/cm^2) on the plane. Homework Equations As of now I think the only relavent equation would be the atom density which is...

Homework Statement In Bohr’s hydrogen atom, the frequency of radiation for transitions between adjacent orbits is νBohr = (En+1−En)/h. Classically, a charged particle moving in a circular orbit radiates at the frequency of the motion, νorbit = v/2πr. Find the ratio νBohr/νorbit for the...

Hi all ! I need some help Homework Statement The nucleus of an hydrogen-like atom is usually treated as a point charge Ze. Using the first order perturbation theory, estimate the error due to this approximation assuming that the nucleus is a sphere of radius R with a uniform charge...

using special relativity m = m0/(1-v^2/c^2) on an electron orbiting with a speed of 2.01 * 10^8 m/s in an atom,estimate the percentage corrections to the n=1 energy in a uranium (Z=92) atom. so to find the energy I first need the reduced mass, u, for En = u*(9e9)^2*e^4*Z^2/2(h bar)^2*n^2. How...

Homework Statement Experimental evidence suggests that the nitrogen atom in ammonia, NH3 , has four orbitals in the shape of a pyramid or tetrahedron. Draw an energy-level diagram to show the formation of these orbitals. (Hint: No electron promotion is required.) Homework Equations...

Homework Statement The first part asks to find the necessary momentum of a "relativistic projectile particle" in order to resolve a diameter of 10^-10m (i.e. the atom). The second part asks to find the corresponding energy of the projectile particle, in GeV. Homework Equations λ = h/p E2 =...

Two quick problems, not sure whether the 2 are related or not: 1) The question is: A sodium atom in one of the states laveled 'lowest excited lvels' remains in that state, on average, for 1.6 x 10^-8 s before it makes a transition to the ground level, emitting a photon with wavelength...

What is the Temperature of an atom moving at the speed of light? Since absolute zero is the lack of activity and energy and since no physical object can move faster than the speed of light What is the temperature of an atom moving at the speed of light? Light is either a particle...

When (what year and by whom?) was it discovered that the hydrogen potential is V=-1/r ? I imagine this was deduced from experimental data... amirite? Quite urgent... From wiki it looks like it was found in teh 1920's but I'm not certain so I just want to check. Thanks in advance

when proton and electron combine to form hydrogen atom(ground state) what is the source of radiation emitted

Homework Statement The average function of the H-atom in its ground state is ψ(\vec{r})=(1/(πa03)1/2exp(-r/a0) a0: Bohr radius a.What is the probability i. P(\vec{r})d3\vec{r} that the electron will be found in the volume d3\vec{r} around \vec{r}? ii. Pdr that the electron will be found...

Find the first radius, the energy of "connection" and the wavelenght of the first risk of Lyman series of a hydrogen atom that electron has been "replaced" for a meson with negative charge with a mass 207*electron mass. Radius: r = (h^2*n^2)/(4pi^2*e^2*k*me) we know all constants so we just...

Homework Statement Determine for the hydrogen atom states 1s and 2p the expectation value of the radius r and the associated mean square error Δr. Homework Equations Wave Functions for 1s and 2p from Demtroeder's Experimental Physics Volume 3 (it says "The normalized complete...

This is a problem that's been bothering me for a while. For electrons "in" hydrogenic atoms, do the electrons in states for which l=0 actually orbit the nucleus, or would they only ever be observed to be moving radially (assuming they could be directly observed in that way). Here's my logic...

There are two cases I could think of: Case 1: The electron is constantly in a state of unrest due to the hiesenburg uncertainty principle, and the ZPE of that electron is caused from the state of its own unrest. Case 2: The electron is constantly in a state of unrest becuase it is...

I'm trying to follow a derivation of the ground state energy of Helium using perturbation theory. I've made it through most of the derivation but I'm stuck at the following integral Homework Statement Find the value of C where C=\frac{1}{(4\pi)^2}\int...

Why is it impossible to change the number of protons of an atom? Is it because the protons are in the nucleus? How can we change the number of neutrons then?