Atomic Definition and 812 Threads

Homework Statement First of all, this is my first post here, so I apologize if I format things incorrectly. I'm working on a Matlab script to evaluate the tunnel ionization rates via the PPT model given the correct set of input parameters. The rate equation I am using contains equations...

Forgive me if this has already been discussed. I've been searching and haven't found it. When summing the spin of an atom in the Russell-Saunders coupling scheme, some texts include the spin of an odd nucleon, and some don't. For example, if an atomic energy state is described as ${3}^P_{2}$...

I did not quite understand the "stimulation" part. How does the photon coming near the excited atom force this atom to emit another, identical (from the physical properties point of view) photon? More precisely, how do the stimulating photon and the atom interact?

Calculate the speed and radial acceleration for an electron in the hydrogen atom. Do the same for the Li++ ion. v = e (4pie0mr)^(-1/2) ar = (v^2)/r r ~ 10^-10 m v = 2.24 x 10^6 The book makes note that we can allow a nonrelativistic treatment since the velocity ~ .007c. And for the lithium...

How does atomic radii decrease when we move left to right in a periodic table? Though the nuclear charge increase as a result of increase in number of protons,the same increase is occurring in number of electrons.

Greetings Physics Forums! This is my first post. A physical phenomena that I know for a long time is that when an atom (let's say hydrogen) has an electron that make a quantum jump from a higher energy state to a lower it emits a photon. Suppose the hydrogen atom is isolated from the external...

Can anyone recommend me some papers explaing how cesium atomic clock works?

I recall a physics teacher demonstrating an experiment where he transferred a droplet of oil to the surface of water and carried out some calculations to determine the radius of a carbon atom. I was hoping to replicate the experiement- However I forget the details. Has anyone seen this...

In an atomic nucleus, there is protons, and neutrons. The protons are positively charged and the repel each other. However, there is an "opposing" that helps to keep the nucleus in a piece instead of breaking apart. Does anyone know what kind of force is this? And what causes this force to be...

An article in Wired concerning a new atomic clock has as part of its lead sentence "The new timekeeper could one day ... detect the slowing of time predicted by Einstein’s theory of general relativity." See http://www.wired.com/wiredscience/2010/02/quantum-logic-atomic-clock/#ixzz0f1IPhJLR...

Do substances radiate particles? Is it the wind brushing up the surface particles of the substance? Do dense materials usually have less smell?

Homework Statement 1. Let -Q charge be uniformly distributed over a sphere radius R. Find f(|\vec{G}|), the atomic form factor. 2. Let the incident xrays have wavelength \lambda, determine the dependence of f(|\vec{G}|) on \theta, the scattering angle. Homework Equations...

Hi, I always heard the textbook presenting the idea that atom is mostly compose of space by giving the analogy that if the whole atom is the size of a stadium then the nucleus would be the size of an eraser in the middle of a stadium, and the electrons flying around the stadium but if this...

Hello everyone. Just a quick question: Could somebody explain to me what atomic concentration is, and whether there is a list of all the atomic concentration of the elements somewhere in the internet. The 1st time I heard the term, I typed it on wikipedia and google, surprisingly the...

I know because E=(n+1/2)*h-bar*omega , and n is an integer , with the integers ranging from zero, to all positive values. Photons are said to be massless physical quantities and according Einstein's theory of special relativity (or general relativity) mass and energy are equivalent. So if a...

I know it isn't the anniversaries of these two horrific and deplorable tragedies and I know this is kind of ancient history for people not directly impacted by this event, but I looked at the past threads in PF and could not find a discussion of this topic, so I thought I would start the first...

i am now studying the Doppler effect in a thermal atomic gas If an atom travels in velocity v along x direction at some time, it emits a photon in some direction the momentum of the emitted photon can be well approximated with the free one thus the momentum of the atom after the...

i am now studying the Doppler effect in a thermal atomic gas If an atom travels in velocity v along x direction at some time, it emits a photon in some direction the momentum of the emitted photon can be well approximated with the free one thus the momentum of the atom after the...

As simple as the questions seems, I can't seem to find an answer. 1. Can atomic hydrogen by chemical reaction, be converted to molecular hydrogen? 2. what happens when putting electrodes in a reaction that would give me atomic hydrogen? would it be collected at the cathode like molecular...

Hi, I have a helium atom in the excited state of (1s,20p), and I am told that it has 4 corresponding atomic terms. I am supposed to "write down the quantum numbers of these 4 atomic terms". As I understand it, an atomic term is specified by the 2S+1LJ notation, where S is the spin quantum...

Hi, How would you determine the relative atomic sizes of a neutral atom and an ion? I can't figure this out. It can't be that all neutral atoms are always smaller than all ions can it? For example, how would I determine if Cl- is smaller or larger than S?. (The answer is that Cl- is...

Hey guys, I'm working on some experiment designs and I'm trying to figure out if its possible to isolate a single atom of a particular element for insertion into an inert gas chamber, so say for eg, i want to take carbon atoms, one at a time, and inject them into a neon gas filled chamber, is...

any can answer this? that why J.J Thomson strike gold by alpha particles in his experiment by which he propose model for atomic structure?

for the calculations in one of my homework questions, i need to use the atomic radii of Fe and Ni, the problem is that every site i come across gives me different values Fe wikipedia 126pm physlink 1.72A chemicool 140pm how do i know which one to "trust" ?

Homework Statement An atomic nucleus is in an excited state. It decays to its ground state with the emission of a gamma ray having energy, Egamma = 24.0 keV. The nucleus has a mass of 9.53e-26 kg. What is the recoil speed of the nucleus? (Note: This may be an inelastic collision)Homework...

Homework Statement Calculate the rest mass of Deuterium nucleus. Homework Equations Is it correct to calculate its mass using hydrogen? i.e. 2*rest mass of hydrogen?.. The Attempt at a Solution As stated in textbook, the rest mass of deuterium = 3.34330*10^-27 kg If it is...

Homework Statement It commonly happens that the hyperfine structure in a transition is dominated by the contribution of an s-electron in one of the levels. What property of s-electrons could be responsible for this? A transition of this kind occurs at 494nm in singly ionised 133Cs between a...

Hi guys, Can someone explain The concept of ELASTICITY on an atomic level. To be clear can somebody please try and elaborate on how does a metal rod or bar or wire start to extend under the influence of an external load. What exactly happens on the interatomic level, say we...

How does the nucleas of an atom get energy?

Let us consider an atomic orbital, for example n=2, l=1, m=0 in Hydrogen. The probability plot is given in the figure attached. This picture can be obtained experimentally: via X-ray and elastic electron scattering. Each negative sub-cloud carries a fractional charge. Fortunately, we have...

The 1st ionization energy decreases from Be to B. This would suggest that the outermost electron is held more loosely in B. Also, considering the electron configurations of Be (1s2 2s2) and B (1s2 2s2 2p1) one would think that in B, the shielding effect of the 2s electrons on the p electron...

Homework Statement The two isotopes of antimony have masses 120.90 and 122.90, with a relative abundance of 57.25% and 42.75% respectively. Using these figures, distinguish clearly between atomic mass, isotopic mass, and mass number. Homework Equations The Attempt at a Solution...

All of my questions that follow revolve around the question of atomic geometry/structure as it relates to quantum mechanics. On every high resolution (1 angstrom, and a few less than 1 angstrom) TEM image I have seen, atoms appear as spheres. I then found a website that claims it has visualized...

how to determine the resolution power of it? has it got anything to do with correlation wavelength? just wondering how it is calculated?

Hi Iwant some inormation about atomic time.Can you help me?

Q: The actual mass of one atom of an unknown isotope is 2.18 x 10^-22g. Calculate the atomic mass of this isotope. `How do I calculate it? help =]

Q: An average dimension for the radius of an atom is 1.0 x 10^-8 cm, and the average radius of the nucleus is 1.0 x 10-^13 cm. Determine the ratio of atomic volume to nuclear volume. Assume that the atom is spherical. [V=4/3(pi)r^3] I already have the volume for both, but how can I determine...

Hi, I'm currently looking into reflectivity and emissivity of metals in sunlight. However, I can't quite grasp how the mechanisms of reflection and emission differ. Emission obviously occurs because an electron is exited by a photon and then is de-excited and emits photon or photons. However...

I was previously under the impression that an atomic electron in its lowest orbit has a larger wavelength than an electron in a higher atomic orbit. I read earlier today that lower orbiting electrons actually have smaller wavelengths. :confused: This seems backwards since electrons...

Calculate the polarizability "a(lpha)" of atomic hydrogen in terms of R Homework Statement A simplified model of a hydrogen atom is that the electron cloud is a sphere of radius R with uniform charge density and total charge -e (The actual charge density in the ground state is nonuniform)...

First question, is atomic packing factor as described in wiki the same as fill factor? If so, how does it relate to the conductivity? Does conductivity increase will the increase in atomic packing factor or fill factor? I don't understand the relationship between conductivity and fill...

My question concerns my understand of the mechanics of the absorption of Photons by the components of atoms. I will use a common real-world example to facilitate my understanding of the concept. 1. When a rock (for example) sits in the sunlight, the rock warms to the touch. I believe this...

I understand that electrons are found inside Atoms within specific orbitals, or quantized distances from the nucleus. There are a maximum number of electrons found within each orbit, etc. etc. I recently read that the reason for this quantized nature of orbitals has to do with the wave...

Can you think about relativity in terms of the motions of atoms as they are subject to intermolecular forces? Is time moving slower for the atom which is accelerating with respect to another? Or, would the macroscopic averaging negate the individual motion of the atoms? Or, is this a...

I have only taken one very intro quantum mechanics class and the furthest we got was solving the Schrodinger equation for the Coulumb potential of the hydrogen atom. So we solved for the allowed energy levels and the wavefunction for the hydrogen atom. We also learned how using the...

Is spontaneous atomic disintegration possible under current knowledge? I mean hypothetically if we could isolate one hydrogen atom in a container how long it would be hydrogen atom? Thanks!

In special relativity the clock hands velocity is represented by: V = v0*(1-v2/c2)^1/2 then: What happen with electrons angular velocity in atomic structure? It may be the same?: V = v0*(1-v2/c2)^1/2 if this could be true what happen with matter?

Homework Statement Barium metal crystallizes in a body centered cubic lattice. The unit cell edge length is 502pm. Calculate the atomic radius of Ba. a) 251 pm b) 217 pm c) 177 pm d) 125 pm e) 63 pm Homework Equations Pythagorean Theorem The Attempt at a Solution A^2 + B^2...

I was thinking that as far as I know, an atomic clock, and a mechanical clock, or a tuning fork clock might be affected differently by gravitation and acceleration. Is there any experimental verification of this? I'm trying to figure out if atoms will decay faster and that is it. Or if...

Homework Statement Couple of questions State the De Broglie Wavelength for electrons with an energy of 50eV and the following is a picture is a diagram of the energy levels in Fe: http://www.freeimagehosting.net/image.php?eeddf8b465.jpg What is the energy required to ionise Fe in in...