Atom Definition and 999 Threads

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. A

    I How can laser detuning excite an atom?

    From Wikipedia and other sources that I am reading, a laser detuning can excite an atom. However, for an atom to become excited its energy must be equal to the energy difference of two states. So how can laser detuning still excite an atom? The frequency from the laser would of course be near...
  2. E

    Find the atom using a quantum oracle

    My attempted solutions was, for example let's say we have 4 atoms, and if i ask the oracle about any two atoms that are connected by edge, i can narrow done some possibilities to two atoms. I'm still not sure where i am going with my solution, but if any of you can think this through and come up...
  3. F

    I Solving the Quantum Mechanics of a Hydrogen Atom

    Hello, I have a little problem understanding the quantum mechanics of a hydrogen atom. Im troubled with the following question: before i measure the state of a (simplified: without fine-, hyperfinestructure) hydrogen atom, which is the right probability density of finding the electron? is it...
  4. J

    A How to obtain the spectrum for a given atom or simple molecule?

    The Bohr atom gave the answer to the spectrum of the hydrogen atom. But the spectra of stars contains many absorption (and sometimes emission) lines, corresponding to most atoms (up to iron, I believe). And atmospheric absorption is also due to absorption of some molecules, such as water...
  5. A

    I How does the collision between two atoms work?

    Considering the quantum mechanical model for an atom, what exactly happens when two atoms (say, two Ca2+ ions in a Brownian motion) collide with each other? As I know, this collision is not like a regular elastic or inelastic collision between two macroscopic objects. Is it mainly due to the...
  6. D

    I The Shadow Of An Atom - False Colour Images Reveal Structure

    I've been adding some renderings I did of the M87 black hole on a different thread and was asked to elaborate on the source of this technique which was investigating images of the shadow of an atom. You can look up the original experiment on Google, as well as observe the final image. The...
  7. A

    B Factors contributing to the atomic mass of an atom

    I was studying about atomic masses and realized that even if we say that the atomic mass unit corresponds to 1/12 of the mass of a carbon atom. why is it that even particular isotopes of elements have atomic mass in decimal values. 1/12 of a carbon atoms mass should equal to the mass of a...
  8. thaiqi

    Why doesn't the atom absorb heat energy when it is low?

    (In my last thread) Mentor Dale said: " An atom in the ground state can absorb energy from the environment including thermal radiation. Once it has done so it will be excited and will no longer be in the ground state. An excited atom can radiate and go to a lower energy state, but an atom in the...
  9. thaiqi

    I Doesn't the atom in ground state radiate?

    According to textbooks, an atom in ground state doesn't radiate. Yet I got some other idea after reading Wu Ta-you's theoretical physics book. I hold the viewpoint that the atom does radiate, and at the same time it absorbs energy from heat radiation in its environment. The energy it radiates...
  10. astrocytosis

    Darwin term in a hydrogen atom - evaluating expectation values

    Homework Statement Homework Equations VD= -1/(8m2c2) [pi,[pi,Vc(r)]] VC(r) = -Ze2/r Energy shift Δ = <nlm|VD|nlm> The Attempt at a Solution I can't figure out how to evaluate the expectation values that result from the Δ equation. When I do out the commutator, I get p2V-2pVp+Vp2. This...
  11. O

    Statistics physics problem -- atom is in the ground state or excited state?

    I am learning for my exam in particle physics. One topic is statistical physics. There I ran into this question: Consider an atom at the surface of the Sun, where the temperature is 6000 K. The atom can exist in only 2 states. The ground state is an s state and the excited state at 1.25 eV is a...
  12. abrogard

    What Difference Does Voltage Level Make to An Atom?

    We could have a copper wire at 10,000 V above a copper plate at 0V. At the end of the wire, one atom of copper. Beneath it: one atom of copper. What is the difference between the two atoms because of this voltage difference? Conventionally the current flows from positive to negative. But...
  13. R

    I Question about one electron hydrogen atom angular moment

    Hi, I'm having trouble understanding angular moment of the one electron hydrogen atom. Solving Schrodinger equation on a referece system (say S) I get the energy eigenstates. They depend on three quantum numbers, n, l, m \frac{-ħ}{2 m}\nabla^{2} \Psi - \frac{e^{2}}{4 \pi \epsilon r} \Psi =...
  14. Another

    Wave function in a hydrogen atom : normalization

    Homework Statement Determined wave function in a hydrogen atom. ## Ψ(r,θ,Φ) = A(x+iy)e^{ \frac{-r}{2a_0}}## << find A by normalization Answer of a question in my book is ## A = -\frac{1}{a_0 \sqrt{8 \pi}} (\frac{1}{2a_0})^{3/2} ## Homework Equations ## \int Ψ^*(r,θ,Φ)Ψ(r,θ,Φ) d^3r = \int \int...
  15. M

    I Can an electron be found outside the atom it belongs to?

    What is the probability of an electron being found outside the atom it belongs to? Is it zero or nonzero?
  16. J

    I Why does a BEC manifest no atom bunching?

    Hello. I have asked Andrew Truscott of the Australian National University on why do lasers not manifest photon bunching like incoherent light does and BEC not manifest any atom bunching. His e-mail reply contains an answer that is a it confusing to me. Can you explain it to me please...
  17. QuarkDecay

    A Nuclear and Atomic energy levels

    I've noticed that in the Shell Model of the nucleus, the order of the energy levels is 1s, 1p3/2, 1p1/2, etc. While in the atomic energy levels it goes 1S 2S 2P, ... But they still take the same amount of particles for each level in both the atomic and nucleus. Am I missing something here? Or...
  18. A

    A Atom positions in buckled silicene

    Hi How can I define atomic positions of buckled silicene? lattice vectors are a_1=a/2(sqrt(3),-1,0) a_2=a/2(sqrt(3),1,0)
  19. S

    I Can an observed atom collapse back into a wave?

    I don't really know where my brain is taking me on this one. I was wondering a couple things.. You set up everything for a Slit Experiment. You shoot an atom and observed it before the slit, then somehow collected the particle. It loops back and shoots it out again, this time with the particle...
  20. B

    Average number of photons in a atom at a given temprature

    Can anny body tell me how do I find the average number of photons in an atom at a given temprature for say lead.
  21. Krushnaraj Pandya

    Energy of Li2+ atom according to Bohr's model

    Homework Statement If n=1 is taken to be the reference of the potential energy, what will be the kinetic and potential energy in second excited state of Li2+? Homework Equations E=-13.6z^2/n^2 The Attempt at a Solution I know KE is independent of reference point, so from the formula above...
  22. P

    Stimulated emission per second per atom?

    Homework Statement We are investigating hydrogen in a plasma with the temperature 4500 ºC. Calculate the probability per atom and second for stimulated emission from 2p to 1s if the lifetime of 2p is 1.6 ns Homework Equations Planks radiation law: ##\rho (f) = \frac{8* \pi...
  23. HCverma

    In coordinate bond, why doesn't the H^+ atom get a negative charge?

    In a coordinate bond, why H^+ atom don't get the negative charge? as an example [NH4]^+ If we split [NH4]^+, we get NH3 + H^+. In NH3, N and 3H atoms have completed their octet and H^+ accepts the lone pair of electrons from the N, As we know H^+ has no any electrons but a proton. If it receives...
  24. HCverma

    When the nucleus of H atom is neutral?

    The nucleus of the H atom is neutral when it has two electrons and one proton (when forming a covalent bond) or it has one electron and one proton.
  25. QuarkDecay

    A What Does 1D Mean in the Term Symbol 2p2 1D for Helium?

    The Atom of Helium is doubly excited in 2p2 1D Can someone explain to me how these energy symbols work? I have a problem with what the 1D means specifically. I know 2p2 means two electrons in the 2p state. The 1 in 1D could be referring to electron being in a singleton, but I don't understand...
  26. HCverma

    Chemistry How to calculate the maximum charge of an atom or a molecule

    Homework Statement How to calculate the maximum charge of an atom or a molecule? As we know the equivalent weight = atomic weight / maximum charge Al, Ca and O2The Attempt at a Solution Al, E = 27/3 = 9 Ca, E = 40/2 = 20 O2, E = 16/2 = 8 I see on the books that the charges of Al, Ca and O2 are...
  27. P

    Probability per atom and per second for stimulated emission to occur

    Homework Statement We are investigating hydrogen in a plasma with the temperature 4500 ºC. Calculate the probability per atom and second for stimulated emission from 2p to 1s if the lifetime of 2p is 1.6 ns Homework Equations ##A=\frac{1}{\Sigma \tau}## $$A_{2,1} = \frac{8*\pi *h *...
  28. HCverma

    12 amu and 1.9924 X 10^-23g express the mass of a atom of C?

    Homework Statement 12 amu and 1.9924 X 10^-23g express the mass of an atom of C? Homework EquationsThe Attempt at a Solution Do 12 amu and 1.9924 X 10^-23g express the mass of an atom of C? As I know, 6.023 X 10^23 atoms of C weighs 12 g, 1 atom of C weighs 1 X 12 / 6.023 X 10^23 = 12 amu...
  29. enter

    Oddly specific number of elements

    There are 118 elements known to man, and some scientists like Feynman think that element 137 might be the end of the Periodic Table. Isn't that oddly specific? To me, it feels like it is completely random and of no significance. What is going on here? Is there a constant that relates to this...
  30. HCverma

    Does 'molar mass' include an atomic weight for single atom?

    Does molar mass include an atomic weight for single atom and molecular weight for molecules?
  31. W

    I How many bits or bytes of information are present in 1 atom

    My guess is the number is huge,but I don't know what transformations from the hip Iwould use to figure this out.
  32. C

    I Pauli principle and coupling term in Weizsäcker formula

    Consider the pairing term in Weizsäcker formula. Here https://en.wikipedia.org/wiki/Semi-empirical_mass_formula#Pairing_term it is claimed that: I don't understand how Pauli exclusion principle should be the cause of this. This term comes from spin-spin interaction (or "coupling"), but I do not...
  33. A

    I What an electron in an atom will do when given more energy

    Hello all, I have a question. Consider an electron in a shell of an atom has energy as 1.0ev and in the next shell it energy should be 2.7eV and the further next level energy is let's say 3.1eV. Means an energy gap of 1.7eV is their between first and second level and an energy gap o 2.1 eV is...
  34. E

    First order perturbation energy correction to H-like atom

    Homework Statement Real atomic nuclei are not point charges, but can be approximated as a spherical distribution with radius ##R##, giving the potential $$ \phi(r) = \begin{cases} \frac{Ze}{R}(\frac{3}{2}-\frac{1}{2}\frac{r^2}{R^2}) &\quad r<R\\ \frac{Ze}{r} &\quad r>R \\...
  35. It's me

    Dirac hydrogen atom vs spin symmetry

    Homework Statement Exact spin symmetry in the Dirac equation occurs when there is both a scalar and a vector potential, and they are equal to each other. What physical effect is absent in this case, that does exist in the Dirac solution for the hydrogen atom (vector potential = Coulomb and...
  36. W

    B Who drew the first model of the atom?

    Does anybody know who first drew (not just described but actually drew, even roughly) a model of the atom like the one below, and when: I'd appreciate it if anybody can point me to an evidence.
  37. A

    A Helium atom, variation method and virial theorem

    I need to calculate the energy of the ground state of a helium athom with the variational method using the wave function: $$\psi_{Z_e}(r_1,r_2)=u_{1s,Z_e}(r1)u_{1s, Z_e}(r2)=\frac{1}{\pi}\biggr(\frac{Z_e}{a_0}\biggr)^3e^{-\frac{Z_e(r_1+r_2)}{a_0}}$$ with ##Z_e## the effective charge considered...
  38. CDL

    Adiabatic Approximation in Hydrogen Atom

    Homework Statement Assume that Planck's constant is not actually constant, but is a slowly varying function of time, $$\hbar \rightarrow \hbar (t)$$ with $$\hbar (t) = \hbar_0 e^{- \lambda t}$$ Where ##\hbar_0## is the value of ##\hbar## at ##t = 0##. Consider the Hydrogen atom in this case...
  39. HastiM

    I Calculating Transition Energies from 2p to 1s: Need Help with Formula?

    I shall calculate the 2p → 1s transition energies for hydrogen, deuterium (one proton plus one neutron in the nucleus), and positronium (bound state of an electron and a positron). My problem with this exercise is that I couldn't find a formula to calculate the transition energies. Can someone...
  40. F

    I Does measuring an atom collapse the wavefunction of its parts?

    Suppose you have an experiment that measures the property of an atom as a whole, maybe you can put it through a double-slit or measure its spin, whatever. Presumably that will collapse the wavefunction that you used to describe the atom in that experiment. Would this entail that in the process...
  41. I

    'A single molecule of H2O' vs 'a single atom of H2O'

    Which one is correct below 1. a single molecule of H2O 2. a single atom of H2O (if this one is correct then what does it mean?)
  42. Kenneth Boon Faker

    B What does the 'space' inside an atom consist of?

    Atoms make up all the material stuff around us, but most of an atom is empty space. The nucleus at the centre of an atom (99.95 percent of its mass) is orbited by tiny electrons (only 0.05 percent or less of the overall atomic mass). And as you've probably heard, an analogy is to think of the...
  43. Sahar ali

    I When Should the Bohr Atom Behave Classically?

    under what condition should the Bohr atom behave classically?
  44. mheruian

    B How the atom was proven to exist?

    How come atom was proven to exist just because the electron was discovered in 1874, atom was like a fad of truth on early 1800s right, where atom was pictured at that time like a small brick of ball and nothing else (no electrons, neutrons, protons, parts, etc) and on that year also, chemistry...
  45. T

    Rutherford model of atom and Bohr model

    Homework Statement Question a) Briefly describe the Rutherford model of the hydrogen atom and mention any inadequacies that it might have. b) Describe the Bohr model of the hydrogen atom, and indicate the significance of the quantum number 'n' in the Bohr model. Homework EquationsThe Attempt...
  46. D

    I Atom Construction: Electrons & Protons

    Am I right to say that an electron in the lowest level of an atom cannot fall into the nucleus because to do so requires it to give up energy in the process and it . does not possesses the energy at this atomic level.Electrons in higher levels can give up energy and fall to a lower level if...
  47. devan

    I Width of one electron shell of a hydrogen atom

    I'm quite new to quantum mechanics. I have a question, I'm coding a small game with my friends and I do understand the orbitals and I've even written a function in java to simulate the probabilities of ONE of those diagrams, but I do not know my scale just yet, can anyone tell me the width of...
  48. Carobouy

    B If you condense an atom, would it make a black hole?

    If you were to condense an atom or group of atoms, the gravitational force would be very large because the atom is 99.9999999999996% empty, so making it 100% full would be like crushing a pound of tin foil into the size of a pen dot. If the density is so much it would make a huuuuge...
  49. AdrianHudson

    I Particle Focusing using EM fields

    Good day all! I have a question that has been in my head bouncing around for a while and I figured the best resource would be here as I can't find anymore related information (Or I am just looking in the incorrect spot). My apologies if this is in the wrong section I wasn't too sure where to...
  50. G

    I Bremmstrahlung in neutral atom collisions

    I found an old paper online (1962) I think, stating that bremmstahlung occurs between different neutral atoms in collisions. Am I correct in assuming that this will result in frequencies outside of the usual line broadening mechanisms? Thanks
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