Simulated annealing‐based optimal control over tunneling process through SDWP and Eckart barrier: A momentum basis representation. Issue 15 (25th April 2017)

• Record Type: Journal Article
• Authors: Talukder, Srijeeta; Chaudhury, Pinaki; Ghosh, Subhasree
• Is Part Of: International journal of quantum chemistry. Volume 117:Issue 15(2017)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2017-04-25
• Subjects: Eckart barrier -- momentum representation -- SDWP -- simulated annealing -- tunneling probability; Quantum chemistry -- Periodicals; 541.28
• DOI: 10.1002/qua.25388
• Languages: English
• ISSNs: 0020-7608

Abstract

Abstract: For a reaction to proceed via tunneling mechanism, it is essential that the reactants will cross the potential barrier ( EP ), where its initial energy ( E 0 ) is below the potential barrier EP . Tunneling probability τ is defined as the probability of having momentum higher than km, where k m = ( 2 m E P ) . In the momentum basis representation, τ can be directly calculated by integrating | ψ ( k ) | 2 from the limit km to infinity, where ψ ( k ) is the wave function in the momentum space. Instead of the continuous basis, if we chose momentum grid space, τ can be expressed as τ = ∑ k i = k m ∞ | ψ ( k i ) | 2 . Our target here is to increase this τ by applying a polychromatic field, so that the reaction rate can be enhanced. By applying Simulated Annealing technique we have designed some polychromatic electric fields, spatially symmetric and asymmetric type, which enhances the tunneling rate in symmetric double well system and Eckart barrier confined in an infinite well. Abstract : Understanding the effect of tunneling in the kinetics of chemical reaction is of paramount importance in modern chemistry. Tunneling probability can be measured directly from the wavefunction when tunneling dynamics is studied in momentum basis. Polychromatic fields can be designed to increase tunneling probability by using a Simulated Annealing optimizer. It is shown that the optimally design polychromatic fields are much efficient to increase tunneling than the monochromatic field of similar field strength and frequency.