الفهرس 
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Abstract
Sedik, Elwallid Shehata “Effect of absolute laser phase on reaction dynamics”. Degree of Doctor of Philosophy, Physics Department, Faculty of Science, Ain Shams University 2009.
Potential surfaces, dipole moments and polarizabilities are calculated by ab-initio(MP2) methods along the reaction paths of the F + CH4 and Cl + CH4 reaction systems. It is found that in general dipole moments and polarizabilities exhibit minima and maxima respectively near the transition state. Interaction with infra red (IR) intense laser fields leads to the possibility of interferences between the dipole and polarizability laser-molecule interactions. The larger dipole moment in the C l + CH4 reaction can lead to the creation of deep wells (instead of energy barriers) and new strongly bound states in the transition state region. This suggests reshaping of potential energy surfaces and possible coherent control of reactivity along reaction path as a function of the absolute phase of the incident field. For ion-molecule reactions such as Li+ + CH4, no barrier is found but nevertheless a maximum occurs in the polarizability where the dipole moment vanishes. This suggests a new way of defining transition states for reactions where no barrier occurs. This also suggests that the electronic rearrangement at the transition state occurs on attosecond time scale.
Key words
Intense laser fields; polarizability; dipole moment; reaction path; unrestricted second order Møller-Plesset calculations (UMP2); X+CH4HX+CH3 (X=F, Cl, Li) reaction; chemical laser reaction; tuning of potential energy barriers; coherent control.