Infrared characterization of environmental samples by pulsed photothermal spectroscopy

¹ Research Centre Rossendorf, Institute of Nuclear and Hadron Physics, PO 51 01 19, 01314 Dresden, Germany
² Research Centre Rossendorf, Institute of Radiochemistry, PO 51 01 19, 01314 Dresden, Germany
³ Research Centre Rossendorf, Central Department Radiation Source ELBE, PO 51 01 19, 01314 Dresden, Germany
⁴ LURE, Bât. 209d, Université de Paris-Sud, BP 34, 91898 Orsay Cedex, France

Corresponding author: W.Seidel@fz-rossendorf.de

Received: 14 April 2003
Revised: 25 July 2003
Accepted: 26 September 2003
Published online: 2 December 2003

Abstract

Low concentration of toxic radioactive metals in environmental samples often limits the interpretation of results of infrared studies investigating the interaction processes between the metal ions and environmental compartments. For the first time, we could show that photothermal infrared spectroscopy performed with a pulsed free electron laser can provide reliable infrared spectra throughout a distinct spectral range of interest. In this model investigation, we provide vibrational absorption spectra of a rare earth metal salt dissolved in a KBr matrix and a natural calcite sample obtained by photothermal beam deflection (PTBD) technique and FT-IR spectroscopy, respectively. General agreement was found between all spectra of the different recording techniques. Spectral deviations were observed with samples containing low concentration of the rare earth metal salt indicating a lower detection limit of the photothermal method as compared to conventional FT-IR spectroscopy.