Excited Definition and 174 Threads

In quantum mechanics, an excited state of a system (such as an atom, molecule or nucleus) is any quantum state of the system that has a higher energy than the ground state (that is, more energy than the absolute minimum). Excitation is an elevation in energy level above an arbitrary baseline energy state. In physics there is a specific technical definition for energy level which is often associated with an atom being raised to an excited state. The temperature of a group of particles is indicative of the level of excitation (with the notable exception of systems that exhibit negative temperature).
The lifetime of a system in an excited state is usually short: spontaneous or induced emission of a quantum of energy (such as a photon or a phonon) usually occurs shortly after the system is promoted to the excited state, returning the system to a state with lower energy (a less excited state or the ground state). This return to a lower energy level is often loosely described as decay and is the inverse of excitation.
Long-lived excited states are often called metastable. Long-lived nuclear isomers and singlet oxygen are two examples of this.

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  1. D

    Bohr model question - transition between first excited state and ground state

    Homework Statement In a hydrogenlike ion with atomic number Z, the energies of the allowed states are given by E(n) = (-13.6eV) (Z^2/n^2) What is the wavelength asociated with the transition between first excited state and ground state of hydrogen-like helium? (He+) Homework...
  2. S

    Estimate the lifetime of the excited state that produced this line.

    Homework Statement An atomic spectrum contains a line with a wavelength centered at 460 nm. Careful measurements show the line is really spread out between 459 and 461 nm. Estimate the lifetime of the excited state that produced this line. Homework Equations Change in Frequency =...
  3. F

    Calculating Wavelength and Energy of Excited Hydrogen Atom | Help Guide

    help please, for question: a hydrogen atom, initially in ground state, absorbs a photon, and is excited to its second excited state. What were the wavelength and the energy of the photon by the atom. Did i do it right. 1/λ = (1.097*10^7)(1/n1^2 - 1/n2^2) 1/λ = (1.097*10^7)(1/1^2 -...
  4. MTd2

    N-pole excited states of the proton?

    Does the proton have n-pole excited states? Or n-pole excited states exist only for A>1?
  5. B

    Excited electrons and spectral lines

    Homework Statement Well,the problem is such : There are two hydrogen atoms.In each atom electrons were excited to the same energy level.Lifetime of one of the excited electrons is t1,when lifetime of other is t2. The question is : Which on of them had more wider spectral line,when during...
  6. Z

    Trying to Understand Molecular Excited States Notation

    Hey guys, I'm an engineering PhD student, and I'm doing some work with laser-induced fluorescence. At the moment, I'm trying to understand some notation about the excited states of nitrogen dioxide. One of the papers I'm looking at, V.M. Donnelly, et al. J. Chem. Phys. 71, 659 (1979), is saying...
  7. Z

    Calculating Excited vs Ground State Ratios in the Sun: A Surprising Discovery

    My book calculates the ratio of probability to find an atom in an excited state vs finding it in the ground state in the sun and gets approx 1/109. Essentially this must mean that the ratio of the multiplicities of the system must also be equal to this, i.e.: \Omega2/\Omega1 = 1/109 How...
  8. N

    Why are nuclear excited states always eigenstates of parity?

    QM says that states which are simultaneous eigenstates of two commuting observables are allowed. If you don't have such states to start with you can construct them with the Gramm-Schmidt orthogonalization procedure. Consider the excited states of a nucleus. (They can be considered eigenstates...
  9. L

    Interaction between two excited hydrogen atoms

    hi all. i am trying to calculate the interaction between two excited hydrogen atoms, using degenerate perturbation theory. but comes up a few problems, any helps will be greatly appreciated. the perturbation has the form: H`=e3/R3(XaXb+YaYb-2ZaZb) where the R is the distancee between two...
  10. S

    How do electrons become excited in an atom

    I was wondering why hot objects glow (such as a heated metal), what I found on wiki: "Thermal radiation is energy emitted by matter as electromagnetic waves due to the pool of thermal energy that all matter possesses that has a temperature above absolute zero. Thermal radiation propagates...
  11. X

    Creating Excited States of Nuclei Without Neutrons: Is it Possible?

    Can one go about creating excited states of a nucleus without using neutrons? For example, Aluminium 26 exists in a ground state that has a half-life of about 70000 years, and decays by beta particle emission. It can also exist in an excited state that decays with a half-life of about 6.3...
  12. P

    Why does the proton have no excited states?

    I've never heard of any excited states of the proton. Why? By "excited state" I mean something with the same composition (uud) that decays to the proton (plus photons etc.) with nearly 100% branching ratio.
  13. A

    Separately excited shunt generator

    I have a question that iv been stuck on for wile. I am in year 2, electronic engineering and I am having a little trouble with this. A separately excited shunt generator has the following nameplate data, 50kW, V(FL) = 125, R(A) = .01 ohms, R(F) = 16 ohms and an excitation voltage of 125 VDC...
  14. G

    Exploring Excited State: Spin and Photon Interactions

    hi i have a question about excited state: let me say you have an atom and then you use light to get the electron to a higher energy level. does this mean, that there is always a spin change, cause as far as i know the spin of a photon is 1. but what happens if you have an electron...
  15. M

    Energy of an atom in an excited state

    Homework Statement An atom which is in an excited state, can emit a photon with the wavelength of 330 nm at during the movement between two "energy niveaus". The last niveau has the energy -4.8 \cdot 10^{-19}J. What is the energy of the atom in the excited state? Homework Equations Not...
  16. dlgoff

    Would you be excited when seeing this?

    A few years ago I borrowed my friends camera and took these photos of one of my moms paintings. Close-up of the signature. Now compare to this signature. I got excited.
  17. P

    Transition of neon from ground state to excited state

    Neon has lowest excited energy at 1(s^2)2(s^2)2(p^5)3(s^1) state. And the excitation energy is about 16.9eV. And next energy is at 1(s^2)2(s^2)2(p^5)3(p^1) state. And the excitation energy is about 19eV. In Franck Hertz experiment with Neon, current decrease at every 19eV, no 17eV. Why...
  18. Z

    How long does it take for a valence electron being excited to conduction band?

    We know in silicon a valence electron can be excited to conduction band if it absorbs one photon(one photon absorption) or two photon(two photon absorption),my question is that it must need a certain amount of time for the electron to 'travel' from the valence band to the conduction band(I...
  19. F

    Why aren't more people excited about experimental physics?

    If I look at physics threads here, I can find hundreds of people who want to do theoretical physics but not so many want to do experimental. Why is that? Most of the beauty in physics has come through experiments, after all. I especially liked the Cavendish experiment which was an awesome...
  20. E

    What is the Uncertainty in the Wavelength of Emitted Photon?

    Homework Statement According to the energy-time uncertainty principle, the lifetime t of a state is inversely proportional to the uncertainty in the energy E. We consider the line λ= 656nm resulting from a transition in a hydrogen atom, from an excited state of lifetime 10-8s. (a) What is...
  21. K

    Engineering Braking a Separately Excited DC Motor: Calculation and Analysis

    Homework Statement A separately excited DC motor with 220V, 970rpm, 100A and Ra=0.05ohms. It is braked by plugging from an initial speed of 1000rpm. I need to calculate i)the resistance to be placed in the armature circuit to limit braking current to twice the full load value, ii)the...
  22. B

    Variational Principle on First Excited State

    I am trying to prove the variational principle on 1st excited state, but have some questions here. The theory states like this: If <\psi|\psi_{gs}>=0, then <H>\geq E_{fe}, where 'gs' stands for 'grand state' and 'fe' for 'first excited state'. Proof: Let ground state denoted by 1, and...
  23. M

    When the electrons in silicon are excited by visible light and jump

    When the electrons in silicon are excited by visible light and jump into the conduction band how do the electrons replace? So for example, wouldn't a solar cell only last for so long if all the valence electrons are excited and converted into current. I am looking at it as if all the valence...
  24. G

    Happy and excited beams of light

    As of this point. I understand the following. 1. there is almost 90% loss when applied to a laser system. 100 watts in 10 watt beam out. 2. when a beam is split there is also a loss, (amount unknown) 3. if you take a 20 watt beam and (with not loss) split it in two and cross the beams...
  25. V

    Probability of being in ground & 1st excited state of widened infinite well

    Homework Statement A particle is initially in the ground state of a one-dimensional infinite square well extending from x=0 to x = L/2. Its wave function, correctly normalized, is given by \psi (x) = \dfrac{2}{\sqrt{L}} \sin{(\dfrac{2 \pi x}{L})}} for 0 \leq x \leq L/2 Suddenly, the right hand...
  26. D

    Question about excited atoms etc.

    A quick question... When you excite electrons or so in molecules, atoms etc., do the molecule/atom change, or what does happen ? I mean, if you have water, and excite an electron, do it turn from "liquid" to "gas", or the other way around, or doesn't it change its structure or what you can...
  27. D

    Calculating Time of Excited Electron in Ground State

    What determines the amount of time that an electron spends in an excited state before it drops back to its ground state? Is the attraction between the electron and the nucleus the cause? Would the electrons in heavy elements spend less time in their excited states? I'm conceptualising an...
  28. E

    Mutual Inductance: Coil 1 Excited, Coil 2 Open Circuited

    I have a very basic question regarding mutual inductance. Consider a basic square loop with two coils wound on opposite sides from each other, with coil one excited while coil two si left open circuited. The total flux linking coil 1 is Φ11 = Φl1+Φ21 where Φ11 is the total flux...
  29. J

    Nuclear models: excited states of 182Ta

    Hi all, I'm doing some test prep for a Nuclear Physics course and working on a past paper. I've attached a photo of the question. The diagram is 3.19 in Krane. The course is based on Krane, and so the relevant chapter is Chp 5: Nuclear Models. Problem description The problem is to explain...
  30. O

    About the excited state of an electron

    hi everyone, I'm a beginner in QM and I have a question. we know that when an electron is hit by a photon, it gains the photon's energy and goes up to the excited state. Here is my question: according to the compton effect, we can interpret the collision of a photon and an electron just...
  31. B

    Fraction of Hydrogen Atoms in First Excited State

    Homework Statement 1. Homework Statement The temperature of the surface of a certain star is 8000 K. Most hydrogen atoms at the surface of the star are in the electronic ground state. What is the approximate fraction of the hydrogen atoms that are in the first excited state (and therefore...
  32. L

    How can I tell when an electronic config is in ground or excited state?

    How can I tell, with an electronic configuration, if an element is in ground or exited state? Also, how can I determine what element it is if it uses a noble gas shortcut? I assume I find the noble gas in brackets, count the atomic number, add it to the elec config outside of the brackets, and...
  33. D

    Excited hydrogen atom and wavelength

    i have been working on this question for quite a while. no help on google, or my textbook at all. A hydrogen atom in its ground state is excited to the n=5 level. It then makes a transition directly to the n=2 level before returning to the ground state. A) What are the wavelengths of the...
  34. L

    Rotational energy of nuclear excited states

    Homework Statement Rotation of a deformed nucleus is predicted to produce nuclear excited states with energies given by E(J)=J(J+1)hbar/2I. The first two excited states of 238 U are Jpi = 2+(0.045MeV) and Kpi=4+(0.148MeV). Show these energies are consistent with rotational excitation stating...
  35. E

    Ground or excited states.Please check.

    Homework Statement State wether atom is in ground or excited state. Homework Equations A.1s22s22p3 B.1s22s22p63s23p64s23d104p55s24d7 C.1s22s22p63s23p64s23d6 The Attempt at a Solution A. Ground because all are filled in order. B.Excited because the 5s sub-shell isn't quite...
  36. S

    Binding energy of an electron in an excited state?

    Homework Statement How much energy is required to remove an electron from a hydrogen atom in a state with n = 8? Homework Equations E = - (1 / 4pi*epsilon_0)(me^4/2(h-bar)^2)(1/n^2) Where E is the total energy of the electron. The Attempt at a Solution I know that if you solve...
  37. A

    Do shielding materials get excited and start reactions?

    In neutron activations, target materials are being beamed by high energy flux, thus making the target materials excited and undergo radioactive decay. Neutron analysis then can be performed after the materials are "cool" enough by placing inside the hood with enough shielding. My question is...
  38. O

    Calculating Probability of Particle in First Excited State

    Homework Statement A particle is in a quantum state defined by: \Phi(x)=0.917\Psi_1+0.316\Psi_2+0.224\Psi_3+a\Psi_4 where \Psi are the eigenfunctions for a particle in a box given by \Psi_n=\sqrt{2/L}sin(npix/L). The corresponding eigenenergies are E_n=1.5n^2eV What is the...
  39. M

    Nuclear Shell Model - Spin-parity of excited states

    Homework Statement The ground state of _{6}Cl^{13} has spin-parity 1/2- and the next three excited states have values of 1/2+, 3/2- and 5/2+. Explain these values in terms of the shell model.The Attempt at a Solution The problem is that i don't know what is being asked of me...i initially...
  40. D

    Excited vs. Ground state masses of atom

    1. In a certain gamma decay process, an excited neon atom emits a gamma-ray that has an energy of 1.630 MeV. The neon atom in the ground state has a mass of 19.992 435 u. What is the mass of the excited neon atom? 2. I am pretty lost here. There must be a formula relating these...
  41. W

    Difference b/w excited state and metastable excited sate?

    difference b/w excited satate and metastable excited sate?and why the time period for m.s.excited state is greater than the common excited state?and how a photon deexite the electron when it is interacted with electron in m.s.excited state? m.s.excite=metstable excited state
  42. B

    Concept of slip speed in Self Excited Induction Generator (SEIG)

    Hi Guys, :smile: In case of an Induction Generator (IG) connected to grid, the rotor runs at super synchronous (above synchronous) speed exhibiting -ve slip. This is possible since the grid frequency is fixed at say, 50Hz. However, in case of a Self Excited Induction Generator (SEIG), it...
  43. N

    Wave mechanics: the ground state and excited state of nitrogen attom

    Homework Statement a) To get a wave function for a situation in which the energy is close to E_0 and the atom is almost certainly in one of the minama of the potential energy , consider the functions \varphi_t(x)=[(\varphi_0(x)+\varphi_1(x))/(2^(1/2)))...
  44. M

    Chemistry Photosystems in Plant Cells: Transferring Excited Electron Energy

    How is the energy of an excited electron sent to another adjacent molecule as in the photosystem of chloroplasts in plant cells?
  45. T

    Why do electrons in excited states decay to the ground state?

    Hello, Non-relativistic quantum mechanics doesn't explain why the electron in the hydrogen atom (for example) "decays" from excited states to the ground state. Which theory does explain this phenomenon (from basic principles) ? Thanks.
  46. F

    Calculating Remaining Kinetic Energy After Excited State

    Excited state?? Homework Statement Initially a hydrogen atom is in its ground stat. An electron with kinetic energy 10.6 eV collides with the atom and excites it. What is the remaining kinetic energy of the electron? A. 13.6 B. 23.9 C. 3.0 D. .4 E. .6 the answer is .6 eV but not...
  47. B

    Maximizing Mechanical Work with Argon in a Pressurized System

    I have a question in regards to using gas to operate a closed system, To utilize the kinetic energy of the gas molecules to do mechanical work. Conventionally atmoshperic air has been used. The system (air) is pressurized to say 60 lbs and you may get 2 or 3 uses from that pressure. Let's say...
  48. P

    Calculating the Excited State Lifetime of 223Ra Nucleus

    Homework Statement the nucleus of 227Th decays to 223Ra and \alpha. the daughter nucleus is left in a short lived excited state and decays down to the ground state with the emission of an 80 keV gamma ray. the natural line width of this gamma ray is .6 keV. what is the lifetime of the excited...
  49. T

    How Are Quantum Numbers Sequenced in a Three-Dimensional Cubic Well?

    This is a question relating to Problem 7-1 in Modern Physics (5th ed.) by Tipler and Llewellyn. Find the energies E311, E222, E321 and construct an energy-level diagram for the three-dimensional cubic well that includes the third, fourth, and fifth excited states. How are these states...
  50. E

    What Is the Likely Spin Parity of an Excited 60Co Nucleus?

    Homework Statement I am asked to determine the most likely I\pi state for an excited 60Co nucleus (a 59Co nucleus that has just been hit by a neutron). I have determined already from the previous part of the problem that the excited state has energy of ~7 MeV compared to the ground state. Not...
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