Infrared photodissociation spectroscopy
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چکیده
The infrared photodissociation spectra of [(CO2)n(H2O)m] (n = 1–4, m = 1, 2) are measured in the 3000–3800 cm range. The [(CO2)n(H2O)1] spectra are characterized by a sharp band around 3570 cm except for n = 1; [(CO2)1(H2O)1] does not photodissociate in the spectral range studied. The [(CO2)n(H2O)2] (n = 1, 2) species have similar spectral features with a broad band at ≈3340 cm. A drastic change in the spectral features is observed for [(CO2)3(H2O)2], where sharp bands appear at 3224, 3321, 3364, 3438, and 3572 cm. Ab initio calculations are performed at the MP2/6-311++G** level to provide structural information such as optimized structures, stabilization energies, and vibrational frequencies of the [(CO2)n(H2O)m] species. Comparison between the experimental and theoretical results reveals rather sizeand composition-specific hydration manner in [(CO2)n(H2O)m]: (1) the incorporated H2O is bonded to either CO2 or C2O4 through two equivalent OH•••O hydrogen bonds to form a ring structure in [(CO2)n(H2O)1]; (2) two H2O molecules are independently bound to the O atoms of CO2 in [(CO2)n(H2O)2] (n = 1, 2); (3) a cyclic structure composed of CO2 and two H2O molecules is formed in [(CO2)3(H2O)2]. a) Author to whom correspondence should be addressed. Revised
منابع مشابه
Structures and Charge Distributions of Cluster Anions Studied by Infrared Photodissociation Spectroscopy
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تاریخ انتشار 2004