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Infrared Spectroscopy and Structure of (NO)(n) Clusters
Hiromichi Hoshina1, Mikhail Slipchenko1, Kirill Prozument1
1Department of Chemistry, University of Southern California , Los Angeles, California 90089, United States.
The Journal of Physical Chemistry. A
|January 13, 2016
Summary
Researchers studied nitrogen oxide clusters using infrared spectroscopy and quantum calculations. They observed specific spectral bands for dimers, trimers, and tetramers, revealing their structures and van der Waals interactions in helium droplets.
Area of Science:
- Physical Chemistry
- Spectroscopy
- Quantum Chemistry
Background:
- Nitrogen oxide (NO) clusters are fundamental molecular systems.
- Understanding their structure and interactions is crucial for chemical physics.
- Helium droplets provide a unique environment for studying weakly bound clusters.
Purpose of the Study:
- To investigate the vibrational spectra of nitrogen oxide clusters (NO)n.
- To determine the structural properties and intermolecular interactions of (NO)n clusters.
- To compare experimental spectroscopic data with quantum chemical calculations.
Main Methods:
- Infrared depletion spectroscopy was employed to probe (NO)n clusters in helium droplets.
- Quantum chemical calculations were performed to predict and interpret spectral features.
- Analysis focused on vibrational bands associated with NO-stretch modes.
Main Results:
- Observed distinct spectral bands for cis-ON-NO dimer at 1868.2 and 1786.5 cm⁻¹.
- Located spectral bands for trimer and tetramer clusters near dimer bands, consistent with calculations.
- Identified a new line assigned to van der Waals bound dimers, stabilized by helium droplet cooling.
Conclusions:
- Experimental and theoretical data reveal the vibrational properties of small nitrogen oxide clusters.
- Trimers are characterized as a dimer with a loosely bound third molecule.
- Tetramers are described as two weakly bound dimers, highlighting cluster assembly mechanisms.
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