TY - JOUR
T1 - Experimental and theoretical characterization of M Si16-, M Ge16-, M Sn16-, and M Pb16- (M=Ti, Zr, and Hf)
T2 - The role of cage aromaticity
AU - Furuse, Shunsuke
AU - Koyasu, Kiichirou
AU - Atobe, Junko
AU - Nakajima, Atsushi
N1 - Funding Information:
This work is partly supported by a grant-in-aid for scientific research (A) (No. 19205004) from MEXT and by the x-ray free electron laser (XFEL) project from Japan Science and Technology Agency (JST). The authors are grateful to Professor S. Yabushita for valuable theoretical discussion on the relativistic effects, and also to Mr. K. Ishibashi for PES measurements. K.K. expresses his gratitude to a research fellowship from the Japan Society for the Promotion of Science for Young Scientist.
PY - 2008
Y1 - 2008
N2 - Silicon (Si), germanium (Ge), tin (Sn), and lead (Pb) clusters mixed with a group-4 transition metal atom [M=titanium (Ti), zirconium (Zr), and hafnium (Hf)] were generated by a dual-laser vaporization method, and their properties were analyzed by means of time-of-flight mass spectroscopy and anion photoelectron spectroscopy together with theoretical calculations. In the mass spectra, mixed neutral clusters of M Si16, M Ge16, and M Sn16 were produced specifically, but the yield of M Pb16 was low. The anion photoelectron spectra revealed that M Si16, M Ge16, and M Sn16 neutrals have large highest occupied molecular orbital-lowest unoccupied molecular orbital gaps of 1.5-1.9 eV compared to those of M Pb16 (0.8-0.9 eV), implying that M Si16, M Ge16, and M Sn16 are evidently electronically stable clusters. Cage aromaticity appears to be an important determinant of the electronic stability of these clusters: Calculations of nucleus-independent chemical shifts (NICSs) show that Si16 4-, Ge16 4-, and Sn16 4- have aromatic characters with negative NICS values, while Pb16 4- has an antiaromatic character with a positive NICS value.
AB - Silicon (Si), germanium (Ge), tin (Sn), and lead (Pb) clusters mixed with a group-4 transition metal atom [M=titanium (Ti), zirconium (Zr), and hafnium (Hf)] were generated by a dual-laser vaporization method, and their properties were analyzed by means of time-of-flight mass spectroscopy and anion photoelectron spectroscopy together with theoretical calculations. In the mass spectra, mixed neutral clusters of M Si16, M Ge16, and M Sn16 were produced specifically, but the yield of M Pb16 was low. The anion photoelectron spectra revealed that M Si16, M Ge16, and M Sn16 neutrals have large highest occupied molecular orbital-lowest unoccupied molecular orbital gaps of 1.5-1.9 eV compared to those of M Pb16 (0.8-0.9 eV), implying that M Si16, M Ge16, and M Sn16 are evidently electronically stable clusters. Cage aromaticity appears to be an important determinant of the electronic stability of these clusters: Calculations of nucleus-independent chemical shifts (NICSs) show that Si16 4-, Ge16 4-, and Sn16 4- have aromatic characters with negative NICS values, while Pb16 4- has an antiaromatic character with a positive NICS value.
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U2 - 10.1063/1.2966005
DO - 10.1063/1.2966005
M3 - Article
C2 - 18715073
AN - SCOPUS:49749100083
SN - 0021-9606
VL - 129
JO - Journal of Chemical Physics
JF - Journal of Chemical Physics
IS - 6
M1 - 064311
ER -