Adsorption Mechanisms of NH3 on Chlorinated Si(100)-2×1 Surface

The potential energy surfaces of ammonia molecule adsorptions on the symmetrically chlorinated Si(100)-$2{\times}1$ surface were explored with SIMOMM:MP2/6-31G(d). It was found that the initial nucleophilic attack by ammonia nitrogen to the surface Si forms a $S_N2$ type transition state, which even...

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Bibliographic Details
Published inBulletin of the Korean Chemical Society Vol. 33; no. 3; pp. 775 - 778
Main Authors Lee, Hee-Soon, Choi, Cheol-Ho
Format Journal Article
LanguageKorean
Published 2012
Subjects
Ammonia
Ab initio
SIMOMM
Silicon surface
Mechanism
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Summary:The potential energy surfaces of ammonia molecule adsorptions on the symmetrically chlorinated Si(100)-$2{\times}1$ surface were explored with SIMOMM:MP2/6-31G(d). It was found that the initial nucleophilic attack by ammonia nitrogen to the surface Si forms a $S_N2$ type transition state, which eventually leads to an HCl molecular desorption. The second ammonia molecule adsorption requires much less reaction barrier, which can be rationalized by the surface cooperative effect. In general, it was shown that the surface Si-Cl bonds can be easily subjected to the substitution reactions by ammonia molecules yielding symmetric surface Si-$NH_2$ bonds, which can be a good initial template for subsequent surface chemical modifications. The ammonia adsorptions are in general more facile than the corresponding water adsorption, since ammonia is better nucleophile.
Bibliography:KISTI1.1003/JNL.JAKO201210348675913
ISSN:0253-2964
1229-5949