title: Enhanced Raman spectrum of lawsone on Ag surface: vibrational analyses, frequency shifts, and molecular geometry.
abstract: The surface-enhanced Raman spectrum of lawsone, a well known natural dye, has been investigated. Activation with KNO(3) or Na(2)SO(4) solution was necessary to enhance the Raman signal, whereas addition of NaCl solution depletes the effects. In the enhanced Raman spectrum, the strong double-bond stretching bands are most distinctive and show large red shifts from those in the infrared and FT-Raman spectra. The observed strong double-bond stretching bands reflect lawsone coordinated perpendicular to the Ag surface. DFT computations have been carried out for the plausible configurations of lawsone coordinated to an adatom on the Ag surface. Lawsone coordinated to an Ag(+) adatom with H(+) released best reproduces the observed vibrational characteristics.
authors.affiliation: Department of Chemistry, University of Incheon, Yonsu-ku, Incheon, Republic of Korea.
authors.forename: Jin-Young
authors.initials: JY
authors.lastname: Heo
authors.forename: Chang-Ho
authors.initials: CH
authors.lastname: Cho
authors.forename: Hye-Seon
authors.initials: HS
authors.lastname: Jeon
authors.forename: Byeong-Seo
authors.initials: BS
authors.lastname: Cheong
authors.forename: Han-Gook
authors.initials: HG
authors.lastname: Cho
mesh_terms: D008958:Models, Molecular; D009285:Naphthoquinones / Q000737:chemistry*; D012834:Silver / Q000737:chemistry*; D013059:Spectrum Analysis, Raman / Q000379:methods*; D013499:Surface Properties
chemical_list: D009285:Naphthoquinones; D012834:Silver; C005090:lawsone