FDM Multiangle ATR Minerals (5900 spectra)
550 cm-1 to 4000 cm-1, single bounce ZnSe ATR crystal
4 cm-1 resolution
38.8 to 58.8 degrees angle of incidence (AOI), small increments
multiangle non-polarized spectra
multiangle Rp, Rs polarized spectra
The FDM Multiangle ATR Minerals offers
(1) a new perspective on mineral ATR/FTIR spectra, and
(2) is the only collection of commercially availble ATR dielectic oxide spectra.
Rp and Rs polarized spectra offer further advantages. With polarization, ATR makes it easy to see the isotropic vs anisotropic character of a given sample, especially with glassy solids. Strongly anisotropic Rp and Rs spectra can differ greatly from the corresponding nonpolarized spectra (refs 1,2). Many of the glassy solids in this library have very large anisotropic differences.
This provides for distinctive spectra that are useful for searching and it gives a new level of understanding about the surface of samples. Automotive lighting manufacturers, and others producing optics from commodity resins, should find this especially appealing. FTIR users working in product failure analysis, forensic trace analysis and other fields will find these data useful and fascinating.
Each multiangle ATR data set was run with a full background spectrum at every angle and polarization. Data collection was automated with motors to select the AOI and polarization and to direct the FTIR system.
The spectra were run on a large diameter (about 3/4") ZnSe ATR crystal with a 45 degree face. The samples used to build this library are all whole objects, not powdered, with a nominally flat surface and lightly clamped to the ATR crystal.
The library is provided with the FDM SearchFaster(tm) software.
ref 1: Ivanovski V, Mayerhöfer TG, Kriltz A, Popp J. IR-ATR investigation of surface anisotropy in silicate glasses. Spectrochim Acta A Mol Biomol Spectrosc. 2017 Feb 15;173:608-617. doi: 10.1016/j.saa.2016.10.027. Epub 2016 Oct 17. PMID: 27776315.
ref 2: Thongnopkun P, Ekgasit S. Attenuated total reflection Fourier transform infrared spectra of faceted diamonds. Anal Chim Acta. 2006 Aug 18;576(1):130-5. doi: 10.1016/j.aca.2006.03.066. Epub 2006 Mar 29. PMID: 17723624.
Keywords: dielectric, properties