What is Energy levels: Definition and 276 Discussions
A quantum mechanical system or particle that is bound—that is, confined spatially—can only take on certain discrete values of energy, called energy levels. This contrasts with classical particles, which can have any amount of energy. The term is commonly used for the energy levels of the electrons in atoms, ions, or molecules, which are bound by the electric field of the nucleus, but can also refer to energy levels of nuclei or vibrational or rotational energy levels in molecules. The energy spectrum of a system with such discrete energy levels is said to be quantized.
In chemistry and atomic physics, an electron shell, or principal energy level, may be thought of as the orbit of one or more electrons around an atom's nucleus. The closest shell to the nucleus is called the "1 shell" (also called "K shell"), followed by the "2 shell" (or "L shell"), then the "3 shell" (or "M shell"), and so on farther and farther from the nucleus. The shells correspond with the principal quantum numbers (n = 1, 2, 3, 4 ...) or are labeled alphabetically with letters used in the X-ray notation (K, L, M, N…).
Each shell can contain only a fixed number of electrons: The first shell can hold up to two electrons, the second shell can hold up to eight (2 + 6) electrons, the third shell can hold up to 18 (2 + 6 + 10) and so on. The general formula is that the nth shell can in principle hold up to 2(n2) electrons. Since electrons are electrically attracted to the nucleus, an atom's electrons will generally occupy outer shells only if the more inner shells have already been completely filled by other electrons. However, this is not a strict requirement: atoms may have two or even three incomplete outer shells. (See Madelung rule for more details.) For an explanation of why electrons exist in these shells see electron configuration.If the potential energy is set to zero at infinite distance from the atomic nucleus or molecule, the usual convention, then bound electron states have negative potential energy.
If an atom, ion, or molecule is at the lowest possible energy level, it and its electrons are said to be in the ground state. If it is at a higher energy level, it is said to be excited, or any electrons that have higher energy than the ground state are excited. If more than one quantum mechanical state is at the same energy, the energy levels are "degenerate". They are then called degenerate energy levels.
μ/T represents the change in entropy if we change the number of particles,, so according to the fundamental assumption of statistical mechanics μ/T should tell us about the tendency of two systems to exchange particles...
but I am having a hard time imagining how rotational or vibrational...
Homework Statement
Determine the no. of energy levels with different values of total spin for a system of N particles with spin 1/2
The Attempt at a Solution
Let f be the no. ways to get a z projection of spin, then
f(\sigma )=Binomial(N,\frac{1}{2}N + \sigma)
Where Binomial(a,b) is a chose b...
Exchange splitting of energy levels of a system??
Hey guys, I was just reading my QM book and came across this;
Homework Statement
Determine the exchange splitting of energy levels of a system of two electrons, regarding the interaction of the two electrons are a perturbation.
My...
I don't get why for hydrogenic atoms the 2s and 2p orbitals have the same energy. i do get it mathematically, but I am thinking that the fact that there are angular nodes in 2p and not in 2s MUST affect the energy!
Does molecular vibrational transition and consequent emission of infrared radiation involve electrons changing energy level? In wikipedia, about vibronic transitions it says "Most processes leading to the absorption and emission of visible light, are due to vibronic transitions. This may be...
Would anyone be able to explain s,p,d,f in detail without using complex math? Also quantum states such a m,l etc. or link me to a site/paper that does?
thanks
Hey all,
Is there a way to rank the energy levels of a rare-earth ion in order of increasing energy just from the spectroscopic terms?
Nd3+ has an electron configuration of [Xe]4f^3, which produces energy levels such as 4I, 4F, 2H, 4S, 2G, 4G, 2D, etc from the electrostatic interaction...
Two quick problems, not sure whether the 2 are related or not:
1) The question is:
A sodium atom in one of the states laveled 'lowest excited lvels' remains in that state, on average, for 1.6 x 10^-8 s before it makes a transition to the ground level, emitting a photon with wavelength...
Given the basic result that the harmonic potential well has the energy levels it has, are there ways to convincingly deduce the qualitative properties of the energy levels given a certain potential well?
Take for example a Morse potential, is there a way to deduce (vague if need be, exact if...
Hi everyone
I'm currently studying the MO theory and ran into some trouble understanding orbital energy levels.
As I have previously read, σ bonds are stronger than ∏ bonds, therefore are lower in orbital energy. However, from the MO theory, the σ2p orbital is actually higher in energy than...
Homework Statement
Given a wire with length a and square base b x b (where a >> b), show that the first 1700 (approximately) levels of the electron in the wire are identical for the one dimensional box, when a = 1m and b = 1mm.
Homework Equations
I know that the allowed energies of...
Homework Statement
We know that:
E=<\psi|H|\psi>
where
H=-\frac{\hbar^2}{2m} \nabla^2 - \frac{Ze^2}{4\pi\epsilon_0 r}
and
\psi=R(r)Y(\theta, \phi)
with
R(r)=\frac{1}{\sqrt{(2n)!}}(\frac{2Z}{na_0})^{3/2}\left(\frac{2Zr}{na_0}\right)^{n-1}e^{-Zr/na_0}
If I want to find the energy, do...
Homework Statement
Why doesn't the energy of the hydrogen atom depend on quantum numbers l or m?
Homework Equations
E = (Z^2) 13.6 eV / n^2
The Attempt at a Solution
Regarding l:
I know that it has to do with the inverse-square law between the distance, r, of the e- and the...
I'm confused about something. If there are an infinite number of energy levels available to an atom, how and why would an ionization need to take place? The electron always has another energy level to occupy once its energy has been raised.
Homework Statement
The equilibrium separation of the atoms in H35CI equals 1.27 x 10-10m. Calculate the energy separation between adjacent lines in the rotational-vibrational spectrum
Homework Equations
E = (n + 1/2)h\omega + h2/ 2I * l(l+1)
I = \mur02 \mu = m1m2/ m1 + m2
The...
Now, from what I understand, Bohr's model of the atom is outdated and flawed. But whenever I imagine energy levels, it is the Bohr's model that comes to mind. Do electrons really orbit around the nucleus? I would assume because of classical physics, even though the electron can be on any portion...
Ok, I know that the S, P, D, and F represent blocks (groups of elements) on the periodic table.
I know that the numbers represent rows on the periodic table.
But what about the arrows? What's with the business of "increasing energy"? Why are the arrows slanted...
One of my 'course aims' is to be able to classify the shell model energy levels in terms of quantum numbers l and n and explain how magic numbers arise.
I'm using this to help to understand it as well as lecture notes. http://hyperphysics.phy-astr.gsu.edu/hbase/nuclear/shell.html
I know...
I have a couple questions related to different energy levels and spin. Our professor taught us one way and the TA a different in our review session. We tried to hash it out in class but had to move on. I suspect both the TA and prof were talking about different things - or maybe stuff we won't...
Homework Statement
This is a two part problem. I think I am pretty close, but I'm quite understanding it. Which sucks because this is probably an extremely easy question.:frown:
I have five particles in a box with S spin. I am to find the ground state of the five particles if they have...
problem is:
(a)write down the spatial or orbital for two-non interacting particles, with the same mass, in a one dimensional well, where the potential energy is zero for 0<x<2a and infinite anywhere else.
(b)What are the energies of the four lowest energy levels for the system in units of...
Homework Statement
hi
this is a problem that puzzles me. it goes like this:
energy/1018 J
ionisation level 0.0
level D
level C
level B
ground state A
1.9
2.1
2.4
4.6
An electron with kinetic energy 2.6 × 1018 J collides inelastically with an electron
in the ground state...
Homework Statement
The carbon-dioxide has nondegenerate vibrational energies εr=(h/2π)ω(r+1);r=0,1,2..., where ω=(1.26*10^14)s^-1. What is the contribution of these vibrational modes to the molar heat capacity of carbon-dioxide gas at T=400K?
Homework Equations...
Homework Statement
This is part of a much larger problem, but I'm stuck on trying to draw an energy band diagram for doped silicon and I'm wondering if it is possible for me to find the energy levels ( E_c, E_v, E_f, and E_i ) in a doped semiconductor knowing only the concentrations? This...
I am writing an essay about what would happen if Planck's constant changed to a much larger number.
What I am having a hard time with is the discretization of energy levels for bound system... how would that change if Plancks constant was larger?
Thanks for all the help in advance.
If you solve Schrodinger's equation for a particle in a box you find the solutions to be sines and cosines. The boundary condition that the wave function must go to zero at the edges of the box then leads to the need for an integral number of wavelengths and in turn quantization of energy. I...
Hi every body and how do you do
first sorry of my weak language because I'm new physical Researcher at KACST & I'm learn English now before go to master degree
so my physical question is about the number of electrons in the first level of energy levels
we know the the first level can't...
Hi everyone,
So I'm doing some research on fluorescence and I'm puzzled. I understand that running a current through fluorescent gasses like neon cause the valence electrons to jump up an energy level, and I understand that photons are emitted when they fall back down into their default...
In "A Prime Case of Chaos" (http://www.ams.org/samplings/math-history/prime-chaos.pdf), the author states that "Physicists ... believe the zeroes of the zeta function can be interpreted as energy levels..." I have two problems with this:
(1) the non-trivial zeroes of the zeta function are...
In "A Prime Case of Chaos" (http://www.ams.org/samplings/math-history/prime-chaos.pdf), the author states that "Physicists ... believe the zeroes of the zeta function can be interpreted as energy levels..." I have two problems with this:
(1) the non-trivial zeroes of the zeta function are...
Hi...
I'm having a little trouble understanding this concept.
An energy level is a level where fx. electrons can be in. Ground state, 1st excited state etc., right ? So if I'm not mistaken, a degenerate state is when two or more different quantum states (Fx. electrons) are in the same...
I'd like to just preface this by saying I'm a non-science major in a science course. The professor mentioned we might need another textbook besides the ones for this particular class. Unlike all of the science/engi majors in the class, I don't have it.
Homework Statement
Using the...
Hi,
I was just wondering if the vibrational energy levels in molecules decay, emitting a photon? or by some other mechanism?
For example, if a laser is used to excite a vibrational mode (Like that in Stokes-Raman Scattering) from say v = 0 to v = 1 state. Will the molecule remain in the v...
hi,
the following question is extremely important so please reply!
in an atom, the energy levels of the electrons are negative and the velocity of the electron increases when the energy decreases.
however, this cannot be the total energy(in relativity) because it does not includes the...
Homework Statement
Greetings everyone
I have been been asked to write a 10 page essay on Quantum Energy levels in atomic, molecular, nuclear and solid state physics. My problem is that this is such a huge topic and my knowledge of quantum energy levels and solid state physics is limited...
I read that each line on a line spectra for an element represents an energy level. Hydrogen only has 1 electron which is in the first energy level so why are there so many lines on the H line spectrum?
what i mean is could it be possible for an alpha particle to acquire energy (by collision or from emission) and subsequently emit a gamma ray?? or does only have one (ground) state??
Homework Statement
Calculate the first three energy leveles for an electron in a quantum well of width 10Angstrom
and infinite walls.
Homework Equations
En=\frac{n2pi2(hbar)2}{2mL2}
The Attempt at a Solution
m=9.109E-31Kg
L=10E-10m
hbar=1.055E-34
En=n2*6.032E-20
My problem...
Homework Statement
How many transitions involving the hydrogen energy levels shown correspond to photons of infrared light? The infrared range is less than 1.8 eV
Homework Equations
Paschen Lines = Infared wavelengths
The Attempt at a Solution
I thought that since Paschen lines =...
Homework Statement
I have having difficulty explaining the splitting of helium atom energy levels for three different cases:
1)Coulomb interaction is ignored
2)Coulomb interaction is present but exchange interaction is neglected
3)Coulomb and exchange interactions are present
The Attempt...
okay this isn't exactly me asking how to solve a question but just to verify the theory in my head.
i need to calculate the 4 lowest energy levels for a 3d box (that has sides (2a,a,a)) and show all the quantum numbers (i imagine it means the x,y,z components of n, l, ml) and give the...
Homework Statement
Consider a neutral carbon atom that has six electrons orbiting the nucleus. Suppose that
five of the electrons are in their lowest states,but the sixth is in a very high state. Why
might the energy levels for the outermost electron be similar to those for the single...
Homework Statement
In the presence of a magnetic field, the energy of an atomic energy level is changed by the quantity:
Emag=g\muBBM
(i) Expain the meaning of the terms in the expression.
(ii) Into how many levels is the ground state of the sodium atom split?
(iii) For each...
Bhor's rule breaking "energy levels"
when Ernest Rutherford's model of planetary system to explain the atomic structure, he was forced to have the regret by the fact that "accelerated charges dissipate their Kinetic energy into EM radiations."
Bhor tried to avoid it.So he engaged the idea of...
Homework Statement
I am somewhat confused about calculating the energy difference between different energy levels with the same principal quantum number (n). Eg. one of the questions that I have requires me to work out the energy difference between 23P2 state and the 23S1 state.Homework...
Are there (available) energy levels of an electron say, at a distance 1m, or 100m or 1km away, and near the moon and beyond that belongs to an atomic nucleus on Earth ?
If yes, then why does it prefer to be within the 10^-10 meter distance from the nucleus ?
Sridhar