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. sumit_1

    The lifetime of the excited states of a hydrogen atom?

    How can we differentiate among the lifetimes of the excited states of the hydrogen atom? The states are: 2p, 2s, 3s, 3p
  2. Pushoam

    Energy needed to remove both electrons from a He atom

    Homework Statement Homework EquationsThe Attempt at a Solution [/B] Both electrons are in 1s orbit. For taking out the second electron, I will have to put slightly more energy than 24.6eV. So, the energy required to remove both electrons should be slightly more than 49.2 eV. So, I...
  3. Lucas Silva

    Gauss' Law: Charge of a Hydrogen Atom

    Suppose the hydrogen atom consists of a positive point charge (+e), located in the center of the atom, which is surrounded by a negative charge (-e), distributed in the space around it. The space distribution of the negative charge changes according to the law p=Ce^(−2r/R), where C is a...
  4. arupel

    I Quantum field theory and the hydrogen atom

    Quantum mechanics does a good job in describing the hydrogen atom. Are there any views either mathematically or conceptually in describing the hydrogen atom?
  5. C

    Find the relation of chemical potentials in chemical reaction In hydrogen atom ionization

    Homework Statement In hydrogen atom ionization H→p+e show that ##μ_H=μ_p+μ_r## Homework Equations G=μN (N is the number of particles) The Attempt at a Solution (1) I think the question should say "Find chemical potential relation AT EQUILIBRIUM", don't you think? (2) My professor said that...
  6. Pushoam

    Wavelength of em radiation of H - atom

    Homework Statement Homework EquationsThe Attempt at a Solution E = (13.6 – 3.4 = 10.2)eV = ## \frac {hc } { \lambda } ## =1.22 * 10^{-5} cm So, the correct option is (a). Is this correct?
  7. M

    Quantum Jump that produces an infrared line?

    1. A certain type of atom has only four energy levels, as shown in the diagram. The "spectral lines" produces by this element are all visible, except for one infrared line. The quantum jump that produces the infrared line is: (see attached file) A) state 4 to 3.B) state 4 to 1.C) state 2 to 1...
  8. Y

    I How to factorize the hydrogen atom Hamiltonian?

    Hello, The hydrogen atom Hamiltonian is $$H=\frac{p^2}{2m} -\frac{e^2}{r}\tag{1}$$ with e the elementary charge,m the mass of the electron,r the radius from the nucleus and p,the momentum. Apparently we can factorize H $$H=\gamma +\frac{1}{2m}\sum_{k=1}^{3}\left(\hat p_k+i\beta\frac{\hat...
  9. Tom MS

    Why Does Diatomic Hydrogen Form Despite Zero Net Electric Field?

    Say you had two isolated hydrogen atoms. Because of the spherical distribution of electronic charge on each hydrogen and the net charge of 0 outside each atom, wouldn't Gauss's law dictate a 0 net electric field outside each atom? If this is the case, why does diatomic hydrogen so readily form...
  10. J

    Determine energy levels of a electron in a hydrogen atom

    Homework Statement When an electron in a hydrogen atom makes a transiton between two levels with prinicipal quantum numbers n1 and n2, light is emitted with wavelength of 658.1 nm. If we assume that the energy levels of the atom are in agreement with the Bohr model, what are n1 and n2...
  11. erik giles

    Light-clock and time dilation [was: Hydrogen atom expressed mathematically]

    [Note from mentor: this thread was originally posted in the Quantum Physics forum.] I am looking for a way to mathematically express the orbit of an electron around the nucleus of a hydrogen atom, while the atom is stationary as well as in motion. Note the orbit of the electron is 3...
  12. I

    Why is there a negative charge on the oxygen atom with the single bond?

    My question is that why is the negative charge on the oxygen atom with the single bond, why not on the oxygen atom with the double bond? I am confused. Source: https://chem-net.blogspot.in/2012/01/simple-procedure-for-writing-lewis.html
  13. N

    Angular Momentum of a hydrogen atom in the 7f state

    Homework Statement A hydrogen atom is in the 7f state. What is the magnitude of its orbital angular momentum? Homework Equations L=sqrt(L(L+1)hbar The Attempt at a Solution L= Sqrt(3(3+1)Hbar) 1.41hbar (we want J*S) 1.41*1.054*10^-34 1.47*10^-34J*S
  14. T

    Kinetic energy of recoil atom in the photoelectric effect

    Homework Statement In the photoelectric effect it is generalley assumed that all the energy is given as kinetic energy to the electron while the atom is neglected. Do not neglect the recoil kinetic energy of the atom and calculate the kinetic energy of the photoelectron and the ionized atom and...
  15. W

    How does the Pauli Exclusion Principle in this problem?

    Homework Statement This is not a homework problem. It's an example in a textbook. 3 electrons. For ##S=3/2##, we have that $$ m_{s_1} = m_{s_2} = m_{s_3} = 1/2 $$ Therefore by the Pauli Exclusion principle, $$ m_{l_1} \neq m_{l_2} \neq m_{l_3} $$ and they take the values ##-1,0,1##...
  16. K

    B How is Bohr's atom model convenient with quantum mechanics?

    Hi. From what I read, according to Quantum mechanics "even though it looks like objects are in definite places, when we get down to ridiculously tiny objects (like electrons) they seem to be not he in anyone place. And everything looks like a hazy clouds of probability."...
  17. R

    Probability of a measured energy for a hydrogen atom

    Homework Statement https://imgur.com/a/8deZc Homework Equations P(E) = ∫φ*(r)ψ(r)dr from -∞ to ∞ The Attempt at a Solution To find the probability, I know I have to use this equation: P(E) = ∫φ*(r)ψ(r)dr from -∞ to ∞ My question is, what is the energy eigenstate, φ*(r)? Is it the measured...
  18. S

    Kinetic energy of an electron or the whole atom to produce heat?

    Does electron really vibrate to produce heat energy or is it atom in whole to produce heat?
  19. E

    B Unveiling the Mysteries of the Electron in an Atom: The Quantum Perspective

    The quantum physicists claim, that an electron has been 'smeared out' in the space around the nucleus. So it seems an electron in the atom is present everywhere at once. Is the next interpretation acceptable? The electron moves with many km/s in an extremely small space. In photography it...
  20. D

    What's the Latest Theory on the Structure of an Atom?

    Hi I'm Dan and new to Physics forums! I'm planning on posting something tomorrow on an alternate theory for the structure of an atom... I thought I would start with something light ;-) By day I'm a Product Owner and have established several successful and unsuccessful companies! I'm...
  21. PainterGuy

    I Atom as a harmonic oscillator of radition

    Hi Q1: I was reading about ultraviolet catastrophe and it was said that atoms were assumed to be harmonic oscillators of radiation. I believe that two harmonic oscillators could have the same frequency but different amplitudes so it would mean that two different atoms (i.e. two harmonic...
  22. Pushoam

    Attractive force in an atom near a point charge q

    Homework Statement Homework EquationsThe Attempt at a Solution Let's consider the primitive model of atom i.e. the nucleus is surrounded by an electron cloud. Let's say that the nucleus has charge qa and it moves a distance d from the center in the equilibrium position. ## E = \frac {kq}...
  23. Pushoam

    Condition of the charge density of atom

    Homework Statement Homework EquationsThe Attempt at a Solution ##\rho = b r \\E =\frac { k r^2} {4ε_0} \\ p ∝ E^a \\E \left ( r=d \right ) = \frac { k d^2} {4ε_0} \\ p = q d \\ d ∝ d^{2a} \\a = ½ \\p ∝ √E ## PART B ##\rho ∝ r^n \\E ∝r^{n+1} \\ p ∝ E^a \\d ∝d ^{{n+1}a} \\## For eq. 4.1 to...
  24. G

    How long for a potassium atom to become an ion again

    If we do electrolysis, using a potassium electrolyte in water, the Na+ ions turn into Na atoms at the cathode. The question is, how long, on average, will it take for the Na atom to react with water and form a Na+ ion again?
  25. Twigg

    I Two-Level Atom Driven by Two Lasers?

    Hey all, I am looking for a reference that derives the optical Bloch equations for a two-level system driven by two near-detuned monochromatic radiation sources. Specifically, I am looking to substantiate a result I derived by following the same procedure as for a two-level atom driven by a...
  26. L

    I Radiative collapse of an electron in a classical atom

    Hello! How do I find how much energy does electron radiate during one revolution if the energy radiation rate is given by Larmor Formula: dE /dt = [(− 2/3)* e2* a2]/ c3. Should I use the chain rule? At the moment I only want a hint how to solve this. With best regards
  27. H

    B Can an atom be in two places at once?

    I have heard that atom can be in two places at the same time. How this could be possible?
  28. Sophrosyne

    B The Dirac equation and the spectrum of the hydrogen atom

    I was reading that one of the successes of the Dirac equation was that it was able to account for the fine structure of some of the differences in the spectrum of the hydrogen atom. But the Dirac equation is about subatomic particles moving at relativistic velocities. But an electron around the...
  29. J

    I Calculate the energy of the electron in a non-H like atom

    Hello mates. I was doing some research about Rydberg atoms, and I came up with this question: what's the energy of an electron in n energy level in an atom which is NOT hydrogen-like, that is, an atom with more than 1 electron? How can we calculate it? What if the electron we are studying is in...
  30. Quantum Velocity

    I How can an atom reach less than absolute zero?

    I read a page about making atom under absolute zero. https://www.livescience.com/25959-atoms-colder-than-absolute-zero.html I don't understand very much, if you know pleas help me. Thanks!
  31. weezy

    I A question about a particle's de Broglie wavelength

    For electron scattering experiment which measures charge radius of the nucleus, it's said that energies of scattering electrons (or protons) must be such that their wavelength size is of the same order as nuclear dimensions. While i understand why this must be true I'm not entirely sure. My...
  32. Erenjaeger

    I Stationary states (The Bohr hydrogen atom)

    why are energies of the stationary states negative ??
  33. Turbotanten

    Find the ionization energy of a simple model atom

    1. Homework Statement A simple model atom is composed of a point-like nucleus with charge ##+Q## and an electron charge distribution $$ \rho(\vec{r})=-\dfrac{\left|Q\right|}{\pi a^2 r}exp(-2r/a) $$ where ##a## is a constant. Show that the ionization energy (the energy to remove the electron to...
  34. Kelly Lin

    Is the Hydrogen Atom Stable for a Potential Behaving as -1/rs?

    Homework Statement An electron in a hydrogen atom does not fall to the proton because of quantum motion (which may be accounted for by the Heisenberg uncertainty relation for an electron localized in the volume with size r). This is true because the absolute value of the Coulomb potential...
  35. Z

    I Why not describing the radiatation of atom spectrum by TDSE

    The radiation of an atom was interpreted by time-independent schrodinger equation:electron was transformed from high energy level state to lower and emit a photon.Could we treat this process through a wavefunction ##{\psi}(t)##? Before emiting,the system's wavefunction is ##{\psi}(0)## and after...
  36. G

    Software to simulate an atom and chemical reactions?

    Hi, I am trying to simulate in 3D a bunch of chemical reactions. Some of them are complex and I would like to be able to just spawn the elements and molecules and watch them collide to see what happens. Is their any free software to do this?
  37. R

    Minimum Kinetic energy of the hydrogen atom

    Homework Statement A hydrogen atom collides with another hydrogen atom at rest. If the electrons in both atoms are in the ground state, what is the minimum kinetic energy of the hydrogen atom such that the hydrogen atom at rest will have its electron in the first excited state after collision...
  38. J

    I Electron jelly model and Hydrogen Atom

    Hi folks, I am reading "Purcell Electricity and Magnetism" and in the problem 1.77 he says: " Imagine a sphere of radius a filled with negative charge of uniform density, the total charge being equivalent to that of two electrons. Imbed in this jelly of negative charge two protons, and assume...
  39. ikihi

    A hydrogen atom transitions from n= 5 state to the ground state

    Homework Statement A hydrogen atom transitions from ni= 5 state down to the ground state. a) What is the energy of photon emitted from the transition of the hydrogen atom? b) What is the ratio of the momentum of the emitted photon to the momentum of an electron which possesses the same kinetic...
  40. B

    I Can an Atom Become a Black Hole?

    If you shrunk an atom down to a certain point would it become a black hole like all matter in the universe can? How big would it be?
  41. T

    Deriving the ionization energy of a hydrogen atom

    Hi, I've just gotten started with basic quantum physics in physics class and we've just talked about ionization energy. It is stated that the energy of a hydrogen atom is -13.60eV (or -2.179aJ). I assume this is the potential energy (and that this is the reason the atom has a lower mass than the...
  42. Dadface

    I Virial theorem as applied to hydrogen atom

    In the virial theorem the numerical value of the average potential energy within a system is exactly twice that of the average kinetic energy. I know the theorem is proved mathematically but to me it seems a coincidence that one value is exactly twice the other value. I find that interesting. I...
  43. D

    Interaction between a neutral atom and an external magnetic field

    Lets suppose that I have a magnetic dipole moment at (0,0,0) pointing to the Z axis, and in the position (X,Y,Z) in the space, I have a Hydrogen atom, I would like to know the exact interaction between the magnetic field created by the magnetic dipole moment in (0,0,0) and the magnetic fields of...
  44. D

    Quick question about hydrogen atom perturbation

    Homework Statement I have already solved the problem, but I don't really understand why the orbital angular momentum in the z-direction has to be taken to 0 ? Homework EquationsThe Attempt at a Solution Suppose the component of orbital angular momentum in the z-direction is...
  45. Leechie

    Perturbation of a Hydrogen atom

    Homework Statement Suppose there is a deviation from Coulomb's law at very small distances, with the mutual Coulomb potential energy between an electron and a proton being given by: $$V_{mod}(r)= \begin{cases} - \frac {e^2} {4 \pi \varepsilon_0} \frac {b} {r^2} & \text {for } 0 \lt r \leq b \\...
  46. PedroBittar

    I Extended hamiltonian operator for the Hydrogen atom

    I am familiar with the usual solution of the hydrogen atom using the associated legendre functions and spherical harmonics, but my question is: is it possible to extend the hamiltonian of the hydrogen atom to naturally encompass half integer spin? My guess is that spin only pops in naturally in...
  47. Leechie

    Calculating potential energy of hydrogen atom

    Homework Statement Calculate ##\left< \frac 1 r \right>## and ##\left< \frac 1 {r^2} \right>## and the expectation value and uncertainty of the potential energy of the electron and proton for a hydrogen atom in the given state. The given state is: $$ \psi_{2,1,-1} \left( r,\theta,\phi \right)...
  48. C

    I How can an atom change from ground to excited state?

    I am currently studying a Foundation Program, which includes chemistry. -I can easily understand the distinguishable characteristics between ground and excited state via writing the electron configuration. -But how can an tom changes from ground to excited state ? And can an atom changes from...
  49. M

    I Why is spin-orbit coupling neglected in Helium atom?

    I was looking at grotrian diagrams for helium and I see that there is no splitting of energy levels due to spin-orbit coupling. In my book it is said that spin-orbit coupling in helium is small and can be neglected but no further explanation is given. At the same time we do spin-spin coupling...
  50. Xilus

    I Equation for modeling atomic spectra of all atoms

    I've seen the equation I think is just for hydrogen. is this just for hydrogen? of course this doesn't return the atomic spectra, it returns the energy. So using E=h*v and Planck's constant. a simple factor of 1/h would return the frequency. right? Energy is directly proportional to frequency...
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