ISSN:
1432-2021
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Geosciences
,
Physics
Notes:
Abstract Absorption spectroscopy in the near infrared, visible and ultraviolet range can detect transitions between various electronic states of the material involved (intraatomic d-d and f-f transitions, intervalence charge transfer and ligand-to-metal charge transfer transitions). While d-d transitions are primarily sensitive to oxidation state, spin state and the geometry of the first coordination shell, intervalence charge transfer transitions can provide information on the spatial arrangement of higher coordination shells. In principle, electronic absorption spectroscopy is a powerful tool to investigate phase transitions involving structural changes or changes in the electronic state (oxidation state, spin state) of various materials. In practice, this method has rarely been applied due to the difficulties in obtaining absorption spectra at high temperature and at simultaneous high temperature and pressure. The major problems ecountered in high T absorption spectroscopy are due to the blackbody radiation of the sample. It is shown that this problem can be completely solved by combining Fourier-transform spectrometers with reflecting microscopes and microheating stages. The application of electronic absorption spectroscopy to the study of the glass transformation and to pressure-induced spin-pairing transitions is discussed in detail.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00207774
