Adsorption dynamics of bifunctional molecules: Allyl methyl ether on Si(001).

Tamam Bohamud,Ulrich Höfer,Michael Dürr

doi:10.1063/5.0045955

Tamam Bohamud, Ulrich Höfer + Show 1 more

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https://doi.org/10.1063/5.0045955

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Abstract

The reaction dynamics of allyl methyl ether (AME) on Si(001) was studied by means of molecular beam techniques. The reaction of this bifunctional molecule comprising an ether and an alkene group was found to proceed via an intermediate state as deduced from the temperature dependence of the initial sticking probability s0. At constant surface temperature Ts, s0 decreases continuously with increasing kinetic energy Ekin, indicating a non-activated adsorption channel. Qualitatively and quantitatively, the energy dependence is almost identical to the adsorption dynamics of diethyl ether on Si(001). We attribute this to a similar nature of the intermediate state, which largely determines the adsorption dynamics. In consequence, this indicates a predominant role of the ether group and a minor influence of the C=C double bond on the adsorption dynamics of AME on Si(001).

Highlights

Adsorption of organic molecules on the Si(001) surface typically proceeds via an intermediate state that is characterized by a relatively weak, non-covalent bond between the functional group of the adsorbing molecules and the surface
Despite the high reactivity of the C==C double bond on Si(001),24,28–32 we show here that the adsorption dynamics is mainly determined by the ether group
We conclude that the C==C double bond as a second functional group in the allyl methyl ether (AME) molecule does not significantly affect the adsorption dynamics into the intermediate state, which are governed by the ether group

Summary

Introduction

Adsorption of organic molecules on the Si(001) surface typically proceeds via an intermediate state that is characterized by a relatively weak, non-covalent bond between the functional group of the adsorbing molecules and the surface. Molecules with different functional groups such as alkenes feature a considerably stronger dependence of s0 on Ekin and a much lower reactivity at high kinetic energy of the incident molecules (Fig. 1). To the best of our knowledge, the effect of different functional groups on the adsorption dynamics of such bifunctional molecules has not been investigated so far

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