title: Estimating atomic sizes with Raman spectroscopy.
abstract: We demonstrate a technique to determine the Van der Waals radius of iodine atoms using Raman spectroscopy. The iodine diatomic molecules are diffused into the nano-scale channels of a zeolite single crystal. We found their polarized Raman spectroscopy, which corresponds to iodine molecule's vibrational motion along the direction of molecular axis, is significantly modified by the interaction between the iodine molecules and the rigid frame of the crystal's nano-channels. From the number of excitable vibration quantum states of the confined iodine molecules determined from Raman spectra and the size of the nano-channels, we estimate the iodine atomic radius to be 2.10±0.05 Å. It is the first time that atomic sizes, which are far beyond the optical diffraction limit, have be resolved optically using Raman spectroscopy with the help of nano-scale structures.
authors.affiliation: Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.
authors.forename: Dingdi
authors.initials: D
authors.lastname: Wang
authors.forename: Wenhao
authors.initials: W
authors.lastname: Guo
authors.forename: Juanmei
authors.initials: J
authors.lastname: Hu
authors.forename: Fang
authors.initials: F
authors.lastname: Liu
authors.forename: Lisheng
authors.initials: L
authors.lastname: Chen
authors.forename: Shengwang
authors.initials: S
authors.lastname: Du
authors.forename: Zikang
authors.initials: Z
authors.lastname: Tang