Potential Barrier

potential barrier

[pə′ten·chəl ′bar·ē·ər]
(physics)
The potential in a region in a field of force where the force exerted on a particle is such as to oppose the passage of the particle through the region. Also known as barrier; potential hill.

Potential Barrier

 

the spatially bounded region of high potential energy of a particle in a field of force on both sides of which the potential energy decreases quite abruptly. The potential barrier corresponds to the repulsive force.

A potential barrier of simple form is illustrated in Figure 1 for the case of linear motion of a particle along the x-axis. When x = x0, the potential energy V(x) assumes a maximum value V0, which is called the height of the potential barrier. A potential barrier divides space into two regions (I and II), in which the potential energy of the particle is less than that in the region (III) within the potential barrier.

In classical mechanics, the passage of a particle through a potential barrier is possible only when the particle’s total energy ℰ—kinetic energy plus potential energy—exceeds the height of the barrier, that is, when ℰ≥ V0. If, however, the energy of the particle is insufficient to surmount the barrier, ℰ< V0, then the particle, moving from left to right, stops upon reaching the barrier at xi and moves in the opposite direction. The potential barrier is a sort of opaque wall or barrier, hence its name, for particles with energy less than its height.

Figure 1

In quantum mechanics, in contrast to classical mechanics, the passage of particles with energy less than V0 through the potential barrier is possible. This phenomenon is called the tunnel effect. It also happens that particles with energy greater than V0 are sometimes reflected from the barrier. These peculiarities of the behavior of particles in quantum physics are directly related to the wave-corpuscle nature of subatomic particles. The tunnel effect is significant only in systems having microscopic dimensions and masses. The narrower the potential barrier and the smaller the difference between the height of the barrier and the total energy of the particle, the greater the probability of tunneling.

References in periodicals archive ?
And while businesses expect the main drivers of growth will be improved marketing, staff recruitment and developing domestic markets, the survey once again confirms that access to finance is still seen as a potential barrier by many of the town's companies.
The council looked into why some people were not opting for the apprenticeship schemes and found that one potential barrier was the apprentice salary.
The shake-up is designed to offer greater competition between the firms by removing a potential barrier to those considering a change.
EPA pointed out in their latest draft lamp specification that lack of LED lamp-color quality is a potential barrier to broader consumer adoption of energy-efficient lighting.
Greyhound racing is not immune from the effects of the double-dip recession but we hope that by bearing some of these administrative costs, a potential barrier to both getting involved with and continuing greyhound ownership is removed.
1), we propose a potential barrier of width, L, and height, [V.
They found that when the electric field pushes the lithium ions towards the graphene sheets, the intercalation process was limiting the rate at which lithium ions could cross the potential barrier into the graphene.
And a potential barrier to the Dutchman remaining at Stamford Bridge in some capacity has been removed after a key figure in the Russian FA claimed he was happy for him to continue his dual role.
The main potential barrier to Johnson moving to the Arms Park is the issue of the soon-to-be-vacant head coach role with the Wallabies.
ph] exp(-[DELTA]E/kT) is often associated with the phonon density that provides the necessary energy for any hop from site i to site j, in fact represents the rate at which a carrier hops over the potential barrier [4].
A potential barrier is the lack of motivation to change the referral process; hence no problem is experienced.
The nearest to the cathode layer of space is filled with inertial ions, forming around the cathode positive spatial potential barrier.

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