We investigate the structures and properties of chiral molecules, clusters, and ions produced in the isolated gas phase using circular dichroism(CD) spectroscopy. CD spectra measured in solution represent only the average CD values of all conformational isomers present in solution. In contrast,  the CD spectroscopy of cold chiral molecules in the gas phase can provide conformation-selective CD values without influence of solvent molecules.

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  We have developed a CD spectroscopic technique that can be applied to low-density gas-phase molecules. Using this CD spectroscopic technique along with various double resonance spectroscopic techniques, we obtain the conformation-specific CD spectra of cold chiral molecules, clusters and ions in the isolated gas phase. By analyzing those spectra, we investigate the structures of chiral molecules and their properties like chirality transfer and chiral recognition in a molecular level.