Barrier Definition and 260 Threads

Basically I'm trying to find out how to find the maximum distance between two deuterium nuclei in order to overcome the coulomb barrier, causing them to fuse. Thanks

Why is it that neutrons evaporate from nuclei more easily than protons do? Intuitively, since protons are electrostatically repelled (in addition to whatever nuclear forces they have in common with neutrons), one would expect protons to be ejected more readily than neutrons. (Maybe this is...

Hey all! I am gearing up for next year to do a senior project, I want to knock it out in my spare time for the next 10 months. Ideas are: 1) Laser guided missile- 2 phase motor, one to go up then again to go to 'lazed' target. 2) Wifi barrier- setup focused jammers to create a 'wall'...

Homework Statement Infinite Potential Barrier particle moving in one dimension is incident upon a potential barrier given by V (x) = Gδ(x) where δ(x) is the Dirac delta function and G is a constant with units of energy times distance. (The delta function must have units of inverse distance...

Homework Statement http://img543.imageshack.us/img543/4598/photosfr.jpg Find dss, dsr and thus hs. Homework Equations trig The Attempt at a Solution dss = hs/(sin[θ]) dsr = hs/(sin[∅]) dss = 3.059/(cos[θ]) dsr = 47.191/(cos[∅]) θ = arctan(hs/3.059) ∅ = arctan(hs/47.191) I have tried...

Homework Statement There isn't an exact problem I'm struggling with, it's one small part of a larger problem, which involves finding the probability protons will penetrate the Coulomb barrier. I'm trying to understand an example in my notes, and the bit that confuses me is attached as an...

Schottky barrier ! ? hi all something i can't understand in the schottky barrier diode i know that when electrons move from semiconductor(n type) to metal a depletion region appears in the n side so potentail difference is created so for electrons to move from S.c to metal they need to...

There is the atmosphere that is composed of 4 parts: the troposphere, the stratosphere, the mesosphere, and the thermosphere. I know that air is a gas made up of molecules. And a gas fills up the container it is contained in, which is the atmosphere. 1Most of the mass of molecules are in the...

Homework Statement Two different ideal gases are separated by a sliding barrier that can move vertically. The gas in the upper chamber 1 has n moles of material, whilst the gas in the lower chamber 2 has 3n moles of material. At T0 the weight of the barrier is such that the volumes of the two...

In QM textbook, there is the solution of shroedinger Eq. on the rectangular potential barrier. The reflection rate can be caculated in each case, E>V0, E=V0 and E<V0. But, I can't find the experiment on the rectangular potential barrier anywhere. Is there anybody who does or sees such an...

Homework Statement I need help with part (iii) and (ii) of the follwoing problem: http://img228.imageshack.us/img228/516/79620850.jpg Homework Equations From my notes transmission coefficient for E<U is: T(E)= \left[ 1+\frac{1}{4} \left( \frac{U^2}{E(U-E)} \right) sinh^2 (\alpha L)...

Hello people, I'm trying to plot probability distributions from the given potential numerically. These are the results (particle coming from the right) https://fbcdn-sphotos-g-a.akamaihd.net/hphotos-ak-prn1/s720x720/546478_516459578368236_1799346634_n.jpg What I want to know is why does...

I am wondering about the barrier in PN junction diode.Due to diffusion negative ions are formed on the P side and Positive ions are formed on the N side of the diode.both opposite sides exert force of attraction and so a line of positive ions and negative ions align along the junction. The...

Homework Statement A proton's energy is 1.30 MeV below the top of a 14.0 fm-wide energy barrier, What is the probability that the proton will tunnel through the barrier? Homework Equations η=\frac{\hbar}{\sqrt{2m(U_{0}-E)}} P_{tunneling}=e^{\frac{-2w}{η}}The Attempt at a Solution I have...

I could use a basic explanation of how half-lives are associated with the fission barrier. Are half-lives still present in induced fission and not just spontaneous fission? Thanks

Interesting. According to the following link: http://www.sciencedaily.com/releases/2012/04/120423143128.htm What do you all make of this?

To anyone that can help me, Hello everyone. I am student from Mechanical Engineering and I am very new to electronic field. I currently doing my final year project which is developing the high voltage discharge circuit for the DBD plasma. The middle electronic elements is the representative...

A wave packet of mean energy E0 is incident on a potential square barrier. The figure below shows stills from a film showing 9 successive stages in interaction. a) True or false? The incident packet at time t = 0 describes many particles, each in a different momentum state. If false, tell...

I am not an expert on Physics and have for the past year been engulfed in work, so I am very rusty. I read a comment online recently that essentially said the laws of physics simply prevent any object from accelerating to the speed of light (infinite energy required?), but do not say that an...

Homework Statement There is a step barrier at x=0, V_0 > E I am given: ψi = e^i(kx−ωt) ---> ψr = R e^i(−kx−ωt) <--- ψt = T e^(−αx−iωt) ---> Part of question I am confused about: State the two boundary conditions satisfied by the wave function at x = 0 and hence find...

Homework Statement 2. The tunnel effect predicts that electrons can "tunnel" through an energy barrier that classical mechanics predicts to be impenetrable. In a suitably fabricated “quantum dot” device, a thin energy barrier may be penetrated in this way. If the barrier is 0.2eV in height...

if ψ=C*e^(kx) + D*e^(-kx) show that the probability current density is Jx=(i*k*hbar/m)[c*conj(D) - conj(C)*D] since Jx= (i*hbar/2m)*[ψ * derivative of conj(ψ) - conj(ψ)*derivative of ψ] ψ=C*e^(kx) + D*e^(-kx) conj(ψ)= conj(C)*e^(-kx) + conj(D)*e^(kx) ψ ' = C*k*e^(kx) - D*K*e^(-kx)...

Hello, A Schottky barrier is said to have rectifying characteristics, which from what I can understand is bad ...but would the rectifying characteristics mean that current passing through the junction would be flat ...level is probably a better way to describe it rather than flat. I only...

I am looking for a book that explains how a Schottky barrier is formed at a semiconductor metal interface. I have found the attached diagram in a source that i cannot see the references for. Does anyone know of a book containing such a diagram and an explanation of the formation of a Schottky...

Homework Statement 224Ra --> 220Rn + \alpha 224Ra --> 212Pb + 12C 224Ra --> 210Pb + 14C Calculate the Q-Values (in MeV) for these decays given their atomic mass excesses (in MeV) are 88225Ra = 18.818 86220Rn = 10.604 82212Pb = -7.557 \alpha = 2.425 82210Pb = -14.743...

Hello. I was womdering does anyone know any good resources of information on Fermi level de-pinning & Schottky barriers? I have been hunting around online, with not much luck. I thought someone here might be able to suggest some things. Thanks. Seán

Hello there :), I have a problem in calculating transmission probability through double barrier potential in electrical field with matlab. While doing some exercises form http://www.nextnano.de/nextnano3/tutorial/1Dtutorial_Transmission_NEGF.htm, I came to the last one, where external field is...

Hello! As far as I know, the Eyring equation is used to calculate the speed of a reaction: k=\frac{{k}_{b}}{h} {e}^{\frac{-\Delta G}{RT}} In my course the teacher used this formula to calculate the flux of a species of ions across a barrier of potential, but I didn't understand very...

Homework Statement I'll try to recreate from my memory the problem we've been assigned on a test more than one month ago. They gave the solution but I either misunderstood or miscopied it. An electron with kinetic energy 5 eV goes from a region with potential V_0=6 eV (let's call this region...

1. Show that as the height of the barrier approaches the electron's incident kinetic energy E an approximation to the transmission that includes just a (the barrier width) and the wave number of the incident electron k=((2mE)^1/2)/(h/2pi) can be obtained. The expression has no Vo term. (Hint...

Homework Statement A particle of mass m goes toward the unidimensional barrier potential of the form V(x)=0 for x\leq 0 and a\leq x and V(x)=V_0 for 0<x<a. 1)Write the corresponding Schrödinger's equation. 2)Calculate the transmission coefficient for the cases 0<E<V_0 and E>V_0. Hint: Check...

Homework Statement Force exerted on a car by a crash barrier as the barrier crushes is F=-(4.5+140s) kN where s is the distance in metres from the initial contact. If a car of mass 2000 kg is traveling at 100 km/h when it hits the barrier the barrier deformation required to bring the car to...

How much energy particles must have in order to overcome the Coulomb Barrier? Or the correct way to ask this is how much temperature is required for this?

Homework Statement A particle is in the ground state of a half harmonic oscillator (V=m/2 w^2 x^2 x>0, and infinity x<0). At t=0, the barrier at x=0 is suddenly removed. Find the possible energy measurements as a function of time and the wavefunction for all times. Homework Equations <H>...

Homework Statement What temperature would be required for two protons to collide if quantum mechanical tunneling is neglected? Assume that nuclei having velocities ten times the root mean square (rms) value for the Maxwell-Boltzmann distribution can overcome the Coulomb barrier (which you can...

Homework Statement V(x) = 0 for x < 0; V0 for 0 < x < a; 0 for x > a Particle of mass m E=V0 Asks for general solution and transmission coefficient. Homework Equations Time-Independent Schrodinger Equation The Attempt at a Solution I've found region I (the left region where x <0) to be...

This is something that has always bugged me about relativity... I must be missing something... Lets say you have a space station sitting stationary out in space... a spaceship approaches it from one side at .75c...another ship approaches the station from the other side, also at .75c, still no...

Homework Statement Let us approximate the Coulomb barrier of a heavy nucleus by a square potential with a height of V0 = 14.8 MeV and a width of L = 13.7 fm. What is the probability that an α particle with an energy of 5.70 MeV will tunnel through this barrier? Homework Equations...

The wavefunction associated with a free particle must be continuous at the barrier and will show an exponential decay inside the barrier. Why it shows an exponential decay inside the barrier? After coming out of the barrier, there is reduced probability for the particle. When there is no loss of...

Suppose that one electron from the end of the universe is emitted to the quantum rectangular barrier potential whose size amouts to galaxy size. This belongs to step potential problem or rectangular barrier potential problem? The textbook on Quantum mechanics doesn't deal with the case...

Homework Statement A 1.1 eV electron has a 10-4 probability of tunneling through a 2.4 eV potential barrier. What is the probability of a 1.1 eV proton tunneling through the same barrier Homework Equations eq 1) T= [1 + V02 sinh2(kL)/4E(V0-E)]-1 or if (kL)>>1 we use eq 2) T=...

Homework Statement An electron with kinetic energy 5 eV (8.01E-19 J) passes through a 3 eV (4.806E-19 J) potential barrier. There are certain widths for this potential barrier in which the transmission probability will equal one hundred percent and the reflection probability will equal zero...

Please explain to me what I'm missing: You can't go faster than the speed of light, because of time dilation. The faster you go, the slower time moves for you as compared to objects at rest, and time would stop for you if you ever went the speed of light. That's what makes C the universal...

Dear All I am having problems with how to draw band diagrams with band bending for Schottky Barriers and PN junctions. My issue is that I don't know how you determine which Fermi level remains fixed at its equilibrium level and which Fermi level moves to align with it when the two materials...

As we know the potential barrier of silicon diode is 0.7V at "Normal Temperature" But if the Temperature is 120 degree Centigrade then what will happen? 1) the Potential Barrier will increase 2) Decrease 3) Remain Same Please Explain also!

Homework Statement I'm asked to calculate the reflection and transmission coefficients for scattering from a potential energy barrier. The potential energy barrier is, V(x)=\frac{\hbar^2}{2m} \frac{\lambda}{b} \delta(x) where \delta (x) is the Dirac delta function. Homework Equations See...

An electron having total energy E=4.46 eV approaches a rectangular energy barrier with U=5.02 eV and L=949 pm. Calculate this probability, which is the transmission coefficient. I thought this would be an easy one, given that T=e-2GL and G=\sqrt{\frac{2m(U-E)}{H}} where H is the...

Hi! I'm struggeling with a quantum mechanical problem. Homework Statement An alpha-particle is "trapped" inside a uraniumcore, and the potential is simplified to 0 for R2 < r V0 for R1<= r <= R2 0 for 0<= r < R1 I have calculated the transmission coefficient T =...

After hours searching the web I was not able to find the unidimensional case "a finite barrier inside a finite well". I would appreciate if someone could give me a reference about it.

Homework Statement Two copper conducting wires are separated by an insulating oxide layer. This layer acts as a square barrier of height 10 eV. Estimate the transmission coefficient for penetration by 7 eV electrons (a) if the layer thickness if 5 nm and (b) if the layer thickness is 1 nm...