What is Atom: Definition and 999 Discussions

The name Atom applies to a pair of related Web standards. The Atom Syndication Format is an XML language used for web feeds, while the Atom Publishing Protocol (AtomPub or APP) is a simple HTTP-based protocol for creating and updating web resources.Web feeds allow software programs to check for updates published on a website. To provide a web feed, the site owner may use specialized software (such as a content management system) that publishes a list (or "feed") of recent articles or content in a standardized, machine-readable format. The feed can then be downloaded by programs that use it, like websites that syndicate content from the feed, or by feed reader programs that allow internet users to subscribe to feeds and view their content.
A feed contains entries, which may be headlines, full-text articles, excerpts, summaries or links to content on a website along with various metadata.
The Atom format was developed as an alternative to RSS. Ben Trott, an advocate of the new format that became Atom, believed that RSS had limitations and flaws—such as lack of on-going innovation and its necessity to remain backward compatible—and that there were advantages to a fresh design.Proponents of the new format formed the IETF Atom Publishing Format and Protocol Workgroup. The Atom Syndication Format was published as an IETF proposed standard in RFC 4287 (December 2005), and the Atom Publishing Protocol was published as RFC 5023 (October 2007).

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  1. L

    QED Hydrogen Atom: Formulating and Solving Problem

    I have a fairly straightforward question: how does one formulate the problem of hydrogen atom with quantum field theoretical treatment? I understand that one can just take Uehling potential and find approximately the bound states' energies and wave functions, but it would not make electron...
  2. R

    Question about H atom orbitals

    Hello, all, I have a question about the wave functions of H atom: for p orbital, wave functions from the Schrodinger equation are p+1, p0, and p-1. In chemistry, people use the linear combination of p+1 and p-1 to generate px and py orbitals. The question is: p+1 and p-1 orbitals are...
  3. C

    Can We See Atoms and Molecules? Exploring the Latest Real Images

    Can someone post the most precise atom or molecule real pictures at present?
  4. jaumzaum

    Radiation absorption by an atom

    When we shine light on an atom, it can absorbs this radiation, stimulating its electrons to jump to a more energetic energy level. This lasts too little time, and when the electrons come back to their original (fundamental) energy level, they emit the same energy they had absorbed before. This...
  5. nukeman

    When looking at a Chemical, what does this mean 99.9 atom % D

    When looking at a Chemical, what does this mean... "99.9 atom % D" Hey, can someone explain to me what this means. Lets use D2o for example (Deuterium oxide) 1 store says "99.999 atom % D" And the other store simply says "DEUTERIUM OXIDE 100% D,99.96% " Can someone please shed some...
  6. F

    How Many Copper Atoms Are in a Cubic Centimeter?

    Can someone please help me on this physics question The mass of a copper atom is 2.50 10-25 kg, and the density of copper is 8 920 kg/m3 . (a) Determine the number of atoms in 1 cm3 of copper. (b) Visualize the one cubic centimeter as formed by stacking up identical cubes, with one...
  7. M

    Be atom splitting into two helium atoms

    Simple and stupid question! A Be atom is traveling with 60 kev kinetic energy and splits into two helium atoms, and the process itself releases 92.2 kev. One helium atom moves at a 30 degree angle with respect to x. find the direction of motion of the second helium atom and find the velocity...
  8. jaketodd

    Electromagnetically Induced Transparency Molecular Atom Selectivity?

    Can electromagnetically induced transparency, be effected on a single atom within a molecule? Thanks, Jake
  9. J

    What physical experiment would tell you how many electrons an atom has

    How did scientists/chemists experimentally determine how many electrons an atom has? Hydrogen, carbon, oxygen, etc... I'm wandering what physical experiment would tell you how many electrons an atom has?
  10. L

    Help solving the TISE for the hydrogen atom

    Homework Statement Hi guys the question is "Write down the time independent Schrödinger equation for the hydrogen atom, and show that the wave function Ψ(r,θ ,φ ) = Ae(−r / aB) is a solution. (A is a normalization constant and aB is the Bohr radius.) What is the energy of the state with this...
  11. C

    Hamiltonian for hydrogen atom?

    When I write down the Hamiltonian for the hydrogen atom why do we not include a radiation term or a radiation reaction term? If I had an electron moving in a B field it seems like I would need to have these terms included.
  12. P

    Li atom and its valence e bound energy.

    Homework Statement Find bond energy of valence electron in principal state in Li atom 2S. If first line of the sharp series is 0.813microm and short wave boundary is 0.349 microm. Homework Equations i think I have to use \tilde{v}=R[( 1/(x-(Δ)) )^2-( 1/(n-(Δ)) )^2] Δ-quantum...
  13. J

    Transition Probability of Hydrogen atom in an electric field

    A hydrogen atom is in its ground state and is subject to an external electric field of E = ε(\hat{x}+\hat{y}+2\hat{z})e-t/\tau I'm confused as to how to compute the matrix elements of the perturbed hamiltonian since this is not in the z direction. Would I have to do something like this...
  14. E

    Energy uncertainty of an atom in an excited state

    Homework Statement A Na atom is in an excited state for a mean time of 1.6 \times 10^{-8}s. Then it jumps to the ground state emitting a photon with 2.105 eV of energy. Find the energy uncertainty of that excited state. Homework Equations The Attempt at a Solution I don't even...
  15. E

    Orbital angular momentum possible values of an electron in a hydrogen atom

    Homework Statement What are the orbital angular momentum possible values for an electron in a hydrogen atom with a principal quantum number n = 3? Homework Equations L = \sqrt{l(l+1)}\hbar The Attempt at a Solution Possible values for l are 0, 1, 2. So, substituting these in...
  16. J

    How to calculate the total energy of an atom

    Homework Statement 1. Consider the boron oxide molecule, BO, in the ground state. (a) Calculate total energies separately for each of B and O atoms (in their ground states). Homework Equations (1 Hartree = 27.212 eV, 1 eV = 23.045 kcal/mol). The Attempt at a Solution Etot =...
  17. Telemachus

    Stern-Gerlach, polarized atom beam.

    Homework Statement In a Stern-Gerlach device, an atom beam with angular impulse J, travels through a magnetic field applied normally to the trajectory. The beam is separated in 2j+1 beams in general. Find the relative intensities for these beams if J=1 and if the beam is polarized with jθ=1 in...
  18. N

    Photon emitted by a hydrogen atom in Lyman series and Balmer series at once ?

    Homework Statement Whenever a photon is emitted by hydrogen atom in the Balmer series, it is followed by a photon in Lyman series . What wavelength does this latter photon correspond to ? Homework Equations Balmer series corresponds to the wavelengths in the visible spectrum and Lyman...
  19. N

    Energy of H Atom in 1st Excited State - 23.8 eV

    Homework Statement What is the energy of H atom in the first excited state if the potential energy in the ground state is taken to be 0 ? Homework Equations Usually the energy of H atom in the ground state is -13.6eV and in the 1st excited state is -10.2eV E(n) = πme2/8ε2h2 Bohr's...
  20. A

    Energy Level Transitions, transition time for e- to change energy states in atom

    Given a simple atom like the Bohr atom (and possibly generalized to any other atom), I know that an electron can transition from one energy level to another, either by absorbing or releasing a photon of a precise hf. How much time does an electron take to make a transition from one energy level...
  21. H

    Characteristic Size of an Atom

    Homework Statement There are a few problems I have with my HW that involve the characteristic size of an atom in a certain state. For example, the hydrogen atom in the ground state. Homework Equations - The Attempt at a Solution I don't know where to begin to find the characteristic...
  22. N

    Calculate Iridium Atom Radius | Material Science

    Hi I am in a material science class and one of my homework questions states: "Calculate the radius of an iridium atom,given that Ir has an FCC crystal structure, a density of 22.4g/cm^3,and an atomic weight of 192.2g/mol." I think I have to use the Pythagorean theorem somewhere but my...
  23. D

    The radius of the Stationary State of a hydrogen atom

    Homework Statement A Hydrogen atom is in a state with n=2? Homework Equations r=an^2 a=.0529 nm The Attempt at a Solution I am confused by my book it says that the radius of a stationary state is r=.0529*2^2=.2116 but I disagree isn't the stationary state n=1 which would mean the...
  24. M

    Find the Initial and Final states of an excited Hydrogen Atom

    Homework Statement A hydrogen atom in an excited state absorbs a photon of wavelength 434 nm. What were the initial and final states of the hydrogen atom? Homework Equations 1/λ=1/91.127 * (1/nf2-1/ni2) The Attempt at a Solution Tried to use the equation, but keeping the initial...
  25. H

    Effect of electron addition to various properties of atom

    Homework Statement Describe what happens to the ionization energy, electronegativity and atomic radius as electrons occupy the next sub level. Homework Equations The Attempt at a Solution My (probably incorrect) answers: Ionization Energy: As electrons occupy the next sub level...
  26. G

    What is the Energy of a Photon Released in Atom Decay with a Change in Mass?

    Homework Statement An atom of mass M decays from an excited state to the ground state with a change in mass of ΔM<<M. In the decay process, the atom releases a photon. Use the laws of energy and momentum to determine the energy of the photon, assuming the atom decays from rest. Homework...
  27. A

    Origin of internal magnetic field in an atom

    What is the origin of the internal magnetic field in an atom (which gives rise to spin-orbit interaction in an electron). The energy associated with this field is calculated using the reference frame of the electron and then returning back to the nucleus reference frame (thomas precision). But...
  28. G

    Calculating the atomic polarizability of an atom

    Homework Statement https://www.physicsforums.com/attachments/51461 https://www.physicsforums.com/attachments/51462 Hi! I got stuck in studying the book "introduction to electrodynamics" written by griffith I attached the related pictures above. The page is p.161-p.162. It's concerned...
  29. P

    Dipole moment and net torque of an atom

    Homework Statement The HCl (hydrochloric acid) molecule has a dipole moment of about 3.4x10-30 C.m. The two atoms are separated by about 1.10-10 m. What is the net charge on each atom? What is maximal torque that this dipole will experience in a 5.104 N/C electric field? How much energy one...
  30. A

    Atom Vibration: Temperature & Conservation of Momentum

    I know this question is probably fairly basic but I had a hard time finding an answer on google. Does a single atom vibrate/jiggle/oscillate if it has a temperature (ie is not at absolute zero)? Is this vibration random in direction? If it is random, wouldn't this violate the law of...
  31. D

    Neurtal hydrogen atom net electric charge and electric field at Bohr radius.

    I am studying for my exam and I have run into this problem. The problem is given here http://faculty.mint.ua.edu/~pleclair/PH253/Homework/Spring_2010/HW6-7_atoms_12Mar10/HW6-7_atoms_12Mar10_SOLN.pdf"],[/PLAIN] it is #9. I don't understand why -e ≠ ∫ρdV from 0 to the bohr radius, a0. If all...
  32. S

    Uncovering the Fate of Muons in Atoms

    I find that I cannot find some simple and basic data - when I search, I find recent articles working on advanced extra experiments, but basic facts are taken for granted there and not repeated. What happens to a muon in an atom? Obviously, a free muon decays μ->e+ν~e+νμ with lifetime...
  33. J

    Lonely Hydrogen Atom in Space (casimir)

    A sole hydrogen atom in a vacuum (negligible gravity). The hydrogen atom has the lowest possible kinetic energy allowed by QM. Given that casimir effects apply... Will the hydrogen atom remain at it's initial lowest kinetic energy state indefinitely or is it possible for it's energy state to...
  34. M

    Oscillation of one molecule or atom

    Hello all, Many Physics texts simply say that atoms "vibrate" when heat energy is transfer to a metal bar when it is heated. Or that molecules vibrate as the result of heat transfer. I'm trying to understand what makes an atom or molecule "move" or oscillate when energy is given to it. If I...
  35. W

    How does the size of He- compare to that of a neon atom?

    I understand that He- is larger than He, but I don't know which is bigger between He- and Ne.. please help??
  36. X

    Maximum unpaired electrons in an atom

    Homework Statement If there are 13 electrons in M shell and one electron in N shell, the the number of unpaired electrons in such atom will be Homework Equations M- shell N- shell The Attempt at a Solution The configuration should be 3s2 3p6 3d5 4s1 hence the answer should be 6
  37. D

    How to calculate critical atom density of a slab reactor?

    I am given a critical bare slab reactor 150cm thick (a0=150cm) consisting of a homogenous mixture of U235 and graphite. I am stuck on the part which asks me to calculate the critical atom dennsity. I have solved for the mass of the fuel in terms of the mass of the moderator. I would solve...
  38. W

    Why an atom can have nonzero toal angular momentum in the ground state?

    In its ground state, an atom has no net electric dipole momentum ,but it can have a nonzero angular momentum. Is this a spontaneous symmetry breaking? why the ground state is not of zero angular momentum?
  39. E

    Hydrogen atom spectrum experiment

    Hi,Everyone! I have a question! We often say hydrogen atom spectrum. But in nature ,it exists in the form of molecular hydrogen. today, I read something about hydrogen atom spectrum experiment. In the experiment ,we use hydrogen lamp. The Hydrogen lamp is a long glass tube filled with Hydrogen...
  40. G

    Sean Carroll's view of the atom

    Here's a pic from Sean Carroll's lectures on Dark Matter and Dark Energy available through the Teaching Company: I just want to double check, there are two types of atoms, if I understand the delayed choice experiment correctly, just the knowledge that you can detect the atom transforms...
  41. X

    Beta Decay of He3 Atom: Electron Emission vs. Shell Occupancy

    Does this decay leave the He3 atom with only one electron? The only decay productsas far as I can tell are the electron and antineutrino, so it seems like the atom would only retain the original H3 electron. Now if that's the case, why is the beta decay electron emitted rather than fitting...
  42. A

    What lies beyond the quark? Unraveling the mysteries of the atom

    Hi, a question I have been asking myself is what where to happen if we where to look deeper into the atom? Is there a point in where there is really nothing? As far as I know it only goes down to quarks. Is the quark the end of it or is there more?
  43. W

    Who first solved the hydrogen atom in quantum mechanics?

    is it pauli or schrodinger? is there any original reference?
  44. fluidistic

    Beryllium atom in a weak magnetic field

    1. Homework Statement and attempt at a solution Considering that the ground state of the beryllium atom is 2s^2 and the first excited state is 2s2p, I was wondering in how many lines would the emission/absorption spectrum be modified in a weak magnetic field. I know that if there's no...
  45. A

    Why atom is structured the way it is?

    Hello guys - my first post! Why do we have neutrons and protons in the center and electrons around them? Was the atom like this since the beginning of the universe(or rather did atom exist in the beginning) or did it get structured in this way after sometime? Did the neutrons, electrons and...
  46. O

    What is the size and behavior of atoms in relation to celestial bodies?

    i've read a theory about dark stars resently and I've got some questions that's been gnawing at my mind, hope i can get some answers here. 1: what is the size of an atom? as in if the nucleus was the sun, where would the electrons be? i know diffrent substances has diffrent atom sizes but for...
  47. A

    How Do You Calculate the Wavelength of an Electron Transition in a Helium Ion?

    Homework Statement He+ ion consists of a nucleus which is an alpha particle plus one orbiting electron.Hence it has a net positive charge. a)Derive an expression for the electron state energies b)what is the wavelength associated with a transition between the lowest two energy states...
  48. A

    Normalization of Radial wavefunction of hydrogen atom

    All I need to evaluate the normalization coefficient. I need a step by step guide. It will be a great help if someone please tell me where can i get the solution (with intermediate steps). I think the solution can be done using the orthogonal properties of associated Laguerre polynomial. I need...
  49. S

    Prove that the Bohr hydrogen atom approaches classical conditions when [..]

    "Prove that the Bohr hydrogen atom approaches classical conditions when [. . .]" Homework Statement The problem and its solution are attached as ProblemSolution.jpg. Homework Equations E_k = chR/(n_k)^2 E_l = chR/(n_l)^2 ΔE = hc/λ hc/λ = chR[1/(n_k)^2 – 1/(n_l)^2] 1/ λ = R[1/(n_k)^2 –...
  50. J

    Why is a hydrogen atom lighter than a electron and a proton

    What exactly is it that makes the energy/mass of a hydrogen atom be lower than that of the electron and proton separately? I am aware that this process is what causes stars to emit light, during nuclear fusion deuterium has a smaller mass than a proton and a neutron so its extra mass/energy is...
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