Machine learning models for molecular potential energy surfaces
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Författare
Typ
Examensarbete för masterexamen
Program
Modellbyggare
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Sammanfattning
Molecular solar thermal storage (MOST) systems is a type of energy storage system
which consist of photo switchable molecules that can convert solar energy into
chemical energy which can be released on demand. One important property of a
MOST system is that it the energy storage time should be long which means that
the so-called back-conversion barrier should be large. Recently an experimental
study showed that a substitution in the ortho position of the molecular photo
switch norbornadiene leads to a significant increase of the back-conversation barrier.
However in the same study the back-conversion barrier was also investigated with
electronic structure calculations and this behavior was not seen. This thesis aimed
to understand this discrepancy by investigating the temperature dependence of the
back-conversion for two derivatives of norbornadiene by combining a machine learning
(ML) method called symmetric gradient domain machine learning (sGDML) with
electronic structure calculations to obtain computationally efficient models describing
the dynamical landscape of the molecules studied. It was seen that sGDML models
could describe the dynamical landscape of such molecules to a good approximation,
however more work is required to obtain models which are accurate enough to to
study the temperature dependence of the back-conversion.
Beskrivning
Ämne/nyckelord
molecular solar thermal storage, photo switches, machine learning, sGDML, potential energy surfaces