TY - JOUR
T1 - Adsorption and Subsequent Reaction of a Water Molecule on Silicate and Silica Cluster Anions
AU - Arakawa, Masashi
AU - Omoda, Tsubasa
AU - Terasaki, Akira
N1 - Funding Information:
The present study was supported by Grants-in-Aid for Scientific Research on Innovative Areas (26108510 and 16H00938) from the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Grant-in-Aid for Young Scientists (B) (26870431) from the Japan Society for Promotion of Science (JSPS), and Kurita Water and Environment Foundation (14D047). The computations were mainly performed using a computing system at the Research Institute for Information Technology, Kyushu University.
Publisher Copyright:
© 2017 American Chemical Society.
PY - 2017/5/25
Y1 - 2017/5/25
N2 - We present reactions of size-selected free silicate, MglSiOm-, and silica, SinOm-, cluster anions with a H2O molecule focusing on H2O adsorption. It was found that H2O adsorption to MglSiOm- with l = 2 and 3 (m = 4-6) is always followed by molecular oxygen release, whereas reactivity of the clusters with l = 1 (m = 3-5) was found to be much lower. On the contrary, in the reaction of SinOm- (n = 3-8, 2n - 1 ≤ m ≤ 2n + 2), a H2O adduct is observed as a major reaction product. Larger and oxygen-rich clusters tend to exhibit higher reactivity; the rate constants of the adsorption reaction are 2 orders of magnitude larger than those of CO adsorption previously reported. DFT calculations revealed that H2O is dissociatively adsorbed on SinOm- to form two SiO3(OH) tetrahedra. The site selectivity of H2O adsorption is governed by the location of the singly occupied molecular orbital (SOMO) on SinOm-. The present findings give molecular-level insights into H2O adsorption on silica and silicate species in the interstellar environment.
AB - We present reactions of size-selected free silicate, MglSiOm-, and silica, SinOm-, cluster anions with a H2O molecule focusing on H2O adsorption. It was found that H2O adsorption to MglSiOm- with l = 2 and 3 (m = 4-6) is always followed by molecular oxygen release, whereas reactivity of the clusters with l = 1 (m = 3-5) was found to be much lower. On the contrary, in the reaction of SinOm- (n = 3-8, 2n - 1 ≤ m ≤ 2n + 2), a H2O adduct is observed as a major reaction product. Larger and oxygen-rich clusters tend to exhibit higher reactivity; the rate constants of the adsorption reaction are 2 orders of magnitude larger than those of CO adsorption previously reported. DFT calculations revealed that H2O is dissociatively adsorbed on SinOm- to form two SiO3(OH) tetrahedra. The site selectivity of H2O adsorption is governed by the location of the singly occupied molecular orbital (SOMO) on SinOm-. The present findings give molecular-level insights into H2O adsorption on silica and silicate species in the interstellar environment.
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U2 - 10.1021/acs.jpcc.6b11689
DO - 10.1021/acs.jpcc.6b11689
M3 - Article
AN - SCOPUS:85020720146
VL - 121
SP - 10790
EP - 10795
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
SN - 1932-7447
IS - 20
ER -