What is Hydrogen atom: Definition and 408 Discussions

A hydrogen atom is an atom of the chemical element hydrogen. The electrically neutral atom contains a single positively charged proton and a single negatively charged electron bound to the nucleus by the Coulomb force. Atomic hydrogen constitutes about 75% of the baryonic mass of the universe.In everyday life on Earth, isolated hydrogen atoms (called "atomic hydrogen") are extremely rare. Instead, a hydrogen atom tends to combine with other atoms in compounds, or with another hydrogen atom to form ordinary (diatomic) hydrogen gas, H2. "Atomic hydrogen" and "hydrogen atom" in ordinary English use have overlapping, yet distinct, meanings. For example, a water molecule contains two hydrogen atoms, but does not contain atomic hydrogen (which would refer to isolated hydrogen atoms).
Atomic spectroscopy shows that there is a discrete infinite set of states in which a hydrogen (or any) atom can exist, contrary to the predictions of classical physics. Attempts to develop a theoretical understanding of the states of the hydrogen atom have been important to the history of quantum mechanics, since all other atoms can be roughly understood by knowing in detail about this simplest atomic structure.

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  1. E

    Question about Quantum Theory regarding hydrogen atom and photon

    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...
  2. J

    Derivation of formula for orbital ranges in hydrogen atom

    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} =...
  3. J

    What are the energy states of a hydrogen atom in a B field?

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

    Understanding Spherical Symmetry in the Hydrogen Atom

    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...
  5. V

    Hydrogen Atom Energy: Ratio of νBohr/νorbit

    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...
  6. J

    Trivia: Potential of the hydrogen atom

    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
  7. S

    The Hydrogen Atom Ground State: Radiation Emission

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

    Probabilty of finding the electron of the hydrogen atom in

    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...
  9. L

    Expectation Values of Radii in the Hydrogen Atom

    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...
  10. S

    Two hydrogen atom with same spin can form H_2?

    As I know from the laws of chemistry,to form H_2 the H atoms must have opposite spin. What if they have the same spin? I mean, can an H atom rotate to swap his spin (i'm not expert of the dynamics of spin), or there is no way to couple them? In the case I have a gas of H with all of them...
  11. fluidistic

    Fine structure, hydrogen atom, principal quantum number 3

    Homework Statement The level n=3 for atoms with 1 electron have the states 3s_{1/2}, 3p_{1/2}, 3p_{3/2}, 3d_{3/2}, 3d_{5/2}. If we ignore the spin-orbit coupling these states are degenerated. Calculate the degeneration due to the the spin-orbit coupling for the levels 3p and 3d for the...
  12. R

    Orbital Frequency of an electron in a hydrogen atom

    Homework Statement In a classical model of the hydrogen atom, the electron moves around the proton in a circular orbit of radius 0.053 nm. What is the electron's orbital frequency? What is the effective current of the electron? Homework Equations Freq * Wavelength = Speed of...
  13. A

    Quantum Mechanics and the Hydrogen Atom

    Calculate the expectation value of the potential energy for an electron in a 1s orbital for a hydrogen atom Ive determined the potential energy operator to be V=-e2/4∏ε0r and a wave function of ψ= (1/4∏)1/2 therefore i get <V> = ∫∫∫ψ*Vψr2sin∅drd∅dphi integrals from 0 to r...
  14. fluidistic

    Second order DE (hydrogen atom)

    Homework Statement The DE y''+\frac{2}{x}y'+ \left [ K+\frac{2}{x} - \frac{l(l+1)}{x^2} \right ]y=0, 0<x< + \infty. appears when working on the hydrogen atom. Find all the values of K (the eigenvalues) that generates solutions of the form \phi (x) such that \phi (x) remains finite when x...
  15. K

    Energy level of hydrogen atom - with the electron replaced by a positron

    Energy level of hydrogen atom -- with the electron replaced by a positron The energy level of a hydrogen atom is given by (without fine structure consideration) Eh = -13.6 eV / n^2 Suppose -- if the electron is replaced by a positron, what would happen to this energy level? The resulting...
  16. B

    Normalise wavefunction of hydrogen atom

    Homework Statement An electron in a hydrogen atom is described by the wavefunction: psi(r) is proportional to (psi(subscript 100)+2psi(subscript 210)-3psi(subscript 32 -1) -4psi(subscript411)) where psi(nlm(subscript l)) are the eigenfunctions of the hydrogen atom with n, l...
  17. fluidistic

    Calculating the Radius & Energy of Bohr's Hydrogen Atom

    Homework Statement 1)Determine the radius of the allowed orbits. Calculate the first orbit of Bohr's model for the hydrogen atom. 2)Show that the energy is quantized. Calculate the energy of an electron on the first orbit (fundamental state of hydrogen atom)Homework Equations L=n \hbar...
  18. J

    Radial Probability Distribution Curve for Hydrogen Atom

    I'm trying to plot the radial probability function for a hydrogen atom. I have the function itself (Psi2*4*pi*r2) my problem is that when I plot the function with angstroms on the x-axis, the y-values are larger than they should be (they look about right if I divide them by the bohr radius in...
  19. O

    Acceleration of electron in hydrogen atom

    Hello, I am currently reading about electromagnetic fields: In one of the examples in the textbook we calculate the electric field of a hydrogen proton. We then compute the electric force acting on the orbiting electron to be 8.2 \times 10^{-8} N So I thought I could get the...
  20. antibrane

    Hydrogen Atom in Magnetic Field

    I am attempting to find the probability, after time t, of a hydrogen atom in a magnetic field \vec{\mathbf{B}}=B_0\hat{\mathbf{z}} to go from \left|n,l,s,j,m_j\right\rangle \longrightarrow \left|n',l',s,j',m_j'\right\rangle where j=l+\frac{1}{2} and j'=l'+\frac{1}{2} or...
  21. Q

    Ehrenfest theorem and the hydrogen atom

    Is there any derivation of the bohr model for hydrogen using Ehrenfest theorem. References are appreciated.
  22. B

    Hydrogen atom to 90% the speed of light

    I do not understand if you accelerate a hydrogen atom to 90% the speed of light its mass is greatly increased. Are the forces that hold it together increased? If not how is it different, will it fall apart? If the forces are increased in relationship to the mass of the atom the energy...
  23. A

    Proving <n_f,l_f,m_l,f|p_j|n_i,l_i,m_l,i> for Hydrogen Atom - Homework Help

    Homework Statement Use [H_{0},r_{j}]=\frac{i\hbar}{\mu}p_{j} for the Hydrogen atom (where the j's denote the jth components in Cartesian coordinates) to prove that <n_{f},l_{f},m_{l,f}|p_{j}|n_{i},l_{i},m_{l,i}>=-i\mu\omega<n_{f},l_{f},m_{l,f}|r_{j}|n_{i},l_{i},m_{l,i}> Homework...
  24. D

    Why Is Calculating Mean Values for a Hydrogen Atom Challenging?

    Homework Statement So I've been racking my brain around the hydrogen mean values. \left\langle \frac{1}{r}\right\rangle=\frac{1}{a_0n^2}, that I can solve with the recurrence relation in Schaum: \left\langle r^k\right\rangle=\int_0^\infty r^{k+2}|R_{nl}(r)|^2dr by simply putting in...
  25. O

    Why doesn't the most common form of the hydrogen atom have a neutron?

    Most common isotopes of He has 2 neutrons, Li has 3 neutrons and so on right, until Z increases to higher numbers and we get to elements like iron, where the nucleus doesn't have equal numbers of protons and neutrons anymore. But why isn't the number of protons and neutrons equal in the most...
  26. M

    Hydrogen atom in ground state: some puzzle

    I noticed many PF threads mention ground state of Hydrogen atom. At the same time it is two body problem considered to be solved by separation of variables. It is true, of course, that we can find basis wave functions (solutions of Shroedinger equation). But why does anybody think, that...
  27. C

    Can Creation and Annihilation Operators Solve the Hydrogen Atom Problem?

    Just a quick question regarding the solution of the hydrogen atom: is it possible to solve the hydrogen atom problem via creation and annihilation operators as is the case with the harmonic oscillator? Any help here greatly appreciated! Crawf.
  28. G

    Hydrogen atom in a gravitational field

    hi does anybody of you know if there is an equation that describes an atom in a gravitational field of a star or something like that (general relativity or Newton)or do you know some results that could tell me something about the magnitude of this energy corrections? do you know a method...
  29. T

    Calculation of the dipole polarizability of the hydrogen atom

    A hydrogen atom placed in an electrical field results in a changed energy level and a changed eigenfunction, compared to the free atom. To examine this effect, we choose a homogenous electrical field of the force F, whose field lines run along parallel to the z-axis. The Schrödinger equation is...
  30. A

    Conversion of hydrogen atom wave function that I don't understand

    Hello! I'm preparing for my quantum mechanics test. In the solutions of an old test I find this conversion, that I don't understand. \Psi = Nze^{-r/2a_0} = Nre^{-r/2a_0}cos\Theta N is the normalization constant, which is to be calculated. I would have guessed that z is the atomic...
  31. S

    Exploring the Instability of Positronium: A Comparison with Hydrogen Atom

    I have a question about the stability of positronium. Positronium consists of an electron and a positron whereas hydrogen consists of an electron and a proton. The energy levels of positronium, ignoring fine structure, are -6.8eV/n2 whereas those for hydrogen are -13.6eV/n2. My question...
  32. Q

    Hydrogen atom - complete orthornormal set

    Hi, I was wondering if the bound solutions to the radial part of the hydrogen atom form a complete set for the functions in L^2(0,\infty). I know that the laguerre polynomials are complete and that they only differ from the radial solutions by factors of x^l * exp, so I thought that they would...
  33. H

    Is a hydrogen free radical just a hydrogen atom?

    Hey, probably a stupid question but I can't seem to find an answer anywhere. Is a hydrogen free radical just a single hydrogen atom? A hydrogen atom has an unpaired electron bound right? Thanks in advance
  34. K

    Collision of a free electron and a hydrogen atom - energies

    Homework Statement An electron of know KE collides with a hydrogen atom in its ground state. With what possible KE may it rebound? KE = 11.5 eV 2. The attempt at a solution I assumed that the electron may either hit an orbiting electron and excite him (maximum layer is n = 2, change in KE...
  35. G

    Hydrogen atom at finitine temperature

    hi i asked myself, is it correct to use the ordinary partition function and cut it off at some value to describe the atom at some finite temperature? or is there a better way to do this calculation? and if i evaluate the partition function for let me say n=2. does this mean, that the...
  36. K

    Hydrogen atom expectation of r^2 check

    I haven't posted any of my working for this as I only want to check my answer. Q. For a hydrogen atom with n=2, l=1, m=0 calculate <r^2> My answer = 0.75 * a^2 where a is the bhor radius. Am I right?
  37. D

    Momentum representation of hydrogen atom

    Homework Statement I need to calculate the probability distribution of 1s and 2p state of hydrogen atom in momentum and in coordinate representations. I have calculated the wave function in coordinate representation, and the dilemma is, do I simply do the Fourier transform for given wave...
  38. B

    Quantum Numbers for Hydrogen Atom Electron

    Homework Statement Define the quantum numbers required to specify the state of an electron in hydrogen. The spatial part of the wave-function describing a particular hydrogen atom has no angular dependence. Give the values of all the angular momentum quantum numbers for the electron...
  39. B

    Hydrogen Atom -> Uncertainty Principle

    Hydrogen Atom ---> Uncertainty Principle Hey guys, I'm having some trouble with this one. [PLAIN]http://img849.imageshack.us/img849/2039/physhw.jpg How do I get started?
  40. S

    Hydrogen atom wave function Help

    Consider a hydrogen atom whose wave function is at t=0 is the following superposition of energy eigenfunctions nlm(r) (r, t=0) = *[2100(r) -3200(r) +322(r) What is the probability of finding the system in the ground state (100? in the state (200)? in the state (322)? In another energy...
  41. S

    Calculating Probabilities and Expectation Values for Hydrogen Atom Wave Function

    Consider a hydrogen atom whose wave function is at t=0 is the following superposition of energy eigenfunctions \psinlm(r) \Psi(r, t=0) = \frac{1}{\sqrt{14}} *[2\psi100(r) -3\psi200(r) +\psi322(r) What is the probability of finding the system in the ground state (100? in the state (200)? in...
  42. A

    Dynamics of electron in Bohr Hydrogen atom

    1. Consider Bohr Hydrogen atom with counter-clockwise electron orbit in the xy plane with intial position r(0)=-a0y. The angular frequency of the orbit is w. Derive an expression for the position of electron at a later time t, r(t) in terms of a0 , w, t, x, and y. Homework Equations...
  43. A

    Real Hydrogen Atom: Exploring Electron Energy Effects

    I've heard that the hydrogen atom that we originally learn about in QM that deals with the Coulomb force is an incomplete description. I'm having trouble understanding all of these effects. When describing the electron energy of the real Hydrogen atom, how do things like the zeeman effect...
  44. C

    Hydrogen atom with discrete nonlinear Schrödinger equation

    Hi everyone, How can I solve hydrogen atom with discrete nonlinear schrödinger equation? Could you help me with the mathematics of that, please?
  45. D

    <r> and <V(r)> in the Hydrogen Atom.

    Hi. I'm a 3rd year undergraduate studying Applied Physics and I'm having some trouble with a problem concerning the Hydrogen Atom. This is my first post so please forgive the sloppy equations. Not really used to writing this stuff out without an equation editor handy! Anyway, the...
  46. A

    Hydrogen atom (HELP ME FAST PLEASE)

    Hi, I'm trying to figure out the solution for the ground state of the hydrogen-atom, however it is not going well. As far as i know, you can supress the angular dependence, because the states of hydrogen (or at least some of them) are spherically harmonic. This way the schr. equation just...
  47. Demon117

    Coulombic interaction between the proton and electron of a hydrogen atom

    In the position representation, its true that we can use operators to represent the coulombic interaction between the proton and electron of a Hydrogen atom. I've never actually given any thought as to what the elements of such an operator would be (in matrix form of course). I know these...
  48. Peeter

    Hydrogen atom. state after L_z measurement

    Homework Statement An initial state is given: {\lvert {\psi(0)} \rangle} = \frac{1}{{\sqrt{3}}} \left( {\lvert {100} \rangle} + {\lvert {210} \rangle} + {\lvert {211} \rangle}\right) An L_z measurement is performed with outcome 0 at time t_0. What is the appropriate form for the ket...
  49. T

    Number of electron of a Hydrogen atom (molecule)

    Hi, If the normalized 1D wave-function of hydrogen atom for n=1, l=0, m_l=0; \psi_{1s}(x)=\frac{1}{\sqrt{\pi} a_{0}^{3/2}}e^{-x/a_{0}} and probability distribution of wave-function, \mid\psi_{1s}(x)^2\mid so integration of rho over all x should give the number of electrons which is equal to...
  50. M

    Hydrogen Atom Tables: Find Zeros of Spherical Bessel Function

    I've searched google for some decent tables but couldn't find any. I'm trying to collect Normalized Spherical Harmonics Associated Legendre Polynomials Zeros of the Spherical Bessel Function Normalized Radius Function for the Hydrogen atom etc. I'm allowed a sheet with as much of these...
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