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الرئيسية / علي بن ابراهيم بن علي اللاحم

علي بن ابراهيم بن علي اللاحم

الجمعة _30 _أغسطس _2013

علي بن ابراهيم بن علي اللاحم
علي بن ابراهيم بن علي اللاحم
دكتوراه
العلوم و التقنية
Loughborough University

مجال التميز

تميز دراسي و بحثي

 

 

البحوث المنشورة

 

البحث (1):

 

عنوان البحث:

Chaotic dynamics in multidimensional transition states 

رابط الوصول:

Link 

تاريخ النشر:

    06/12/2012

موجز عن البحث:

 

The crossing of a transition state in a multidimensional reactive system is mediated by invariant geometric objects in phase space: An invariant hyper-sphere that represents the transition state itself and invariant hyper-cylinders that channel the system towards and away from the transition state. The existence of these structures can only be guaranteed if the invariant hyper-sphere is normally hyperbolic, i.e., the dynamics within the transition state is not too strongly chaotic. We study the dynamics within the transition state for the hydrogen exchange reaction in three degrees of freedom. As the energy increases, the dynamics within the transition state becomes increasingly chaotic. We find that the transition state first looses and then, surprisingly, regains its normal hyperbolicity. The important phase space structures of transition state theory will, therefore, exist at most energies above the threshold.

 

 

 

المؤتمرات العلمية:

 

المؤتمر (1):

 

عنوان المؤتمر:

XXXIII Dynamics Days Europe Conference  

تاريخ الإنعقاد:

    03/06/2013

بلد ومكان الإنعقاد:

Campus de Montegancedo, Madrid. Spain

طبيعة المشاركة:

Poster

عنوان المشاركة:

Chaotic dynamics in multidimensional transition states 

موجز عن المشاركة

Many chemical reactions can be described as the crossing of an energetic barrier. This process is mediated by an invariant object in phase space. One can construct a normally hyperbolic invariant manifold (NHIM) of the reactive dynamical system that can be considered as the geometric representation of the transition state itself. It is an invariant sphere. The NHIM has invariant cylinders (reaction channels) attached to it. This invariant geometric structure survives as long as the invariant sphere is normally hyperbolic. We applied this theory to the hydrogen exchange reaction in three degrees of freedom.


Energies high above the reaction threshold, the dynamics within the transition state becomes partially chaotic. We have found that the invariant sphere first ceases to be normally hyperbolic at fairly low energies. Surprisingly normal hyperbolicity is then restored and the invariant sphere remains normally hyperbolic even at very high energies.

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