The dynamics of Brownian motion of a particle whose position is represented by x under a square-well potential which has infinite and finite barriers at x = 0 and x = u, respectively, and elsewhere is flat has been investigated and exact results are obtained. Particularly when the potential depth in
Escape by diffusion from a square well across a square barrier
β Scribed by B.U. Felderhof
- Publisher
- Elsevier Science
- Year
- 2008
- Tongue
- English
- Weight
- 259 KB
- Volume
- 387
- Category
- Article
- ISSN
- 0378-4371
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β¦ Synopsis
The problem of escape of a particle by diffusion from a square potential well across a square barrier is studied on the basis of the one-dimensional Smoluchowski equation for the space-and time-dependent probability distribution. For the model potential the Smoluchowski equation is solved exactly by a Laplace transform with respect to time. In the limit of a high barrier the rate of escape is given by an asymptotic result similar to that derived by Kramers for a curved well and a curved barrier. An approximate analytic formula is derived for the outward time-dependent probability current in terms of the width and depth of the well and the width and height of the barrier. A similar expression holds for the complete probability distribution.
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