title: Fine structures in refractive index of sapphire at the L(II,III) absorption edge of aluminum determined by soft x-ray resonant reflectivity.
abstract: The optical constants of sapphire crystal (α-Al(2)O(3)) and amorphous Al(2)O(3) in the soft x-ray region (67-85 eV) around the aluminum LII,IIIabsorption edge (73.1 eV) are determined by angle-dependent x-ray reflectivity. The differences between the optical constant values of both the samples are discussed. The fine structures obtained in the absorption of crystalline sapphire are explained. An absorption feature at 70.2 eV is observed for the first time for crystalline alumina. Both datasets are compared to the tabulated values of Henke et al. [At. Data Nucl. Data Tables 54, 181 (1993)], Weaver et al. [Physik Daten, Physics Data: Optical Properties of Metals (Fach-information zentrum, 1981), Vols. 18-1 and 18-2], and [Handbook of Optical Constants of Solids II (Academic, 1991)].
authors.affiliation: Indus Synchrotron Utilization Division, Raja Ramanna Centre for Advanced Technology, Indore, India. arijeet@rrcat.gov.in
authors.forename: Arijeet
authors.initials: A
authors.lastname: Das
authors.forename: Rajkumar K
authors.initials: RK
authors.lastname: Gupta
authors.forename: Mohammed H
authors.initials: MH
authors.lastname: Modi
authors.forename: Chandrachur
authors.initials: C
authors.lastname: Mukherjee
authors.forename: Sanjay K
authors.initials: SK
authors.lastname: Rai
authors.forename: Aniruddha
authors.initials: A
authors.lastname: Bose
authors.forename: Tapas
authors.initials: T
authors.lastname: Ganguli
authors.forename: Satish C
authors.initials: SC
authors.lastname: Joshi
authors.forename: Gyan S
authors.initials: GS
authors.lastname: Lodha
authors.forename: Sudip K
authors.initials: SK
authors.lastname: Deb