Electronic spectra of potassium bromide containing thallium II. Emission spectrum excited at 2537 Å
1974; Elsevier BV; Volume: 8; Issue: 5 Linguagem: Inglês
10.1016/0022-2313(74)90080-5
ISSN1872-7883
AutoresP. W. M. Jacobs, Sheila Anne Thorsley,
Tópico(s)Catalytic Processes in Materials Science
ResumoThe emission spectrum of KBr: Tl+ excited at 2537 Å has been measured in the temperature range 15–296°K. At low temperatures the spectrum consists of a prominent band at 4.01 eV, a much smaller band at 3.40 eV and a very small band at 3.15 eV. The last does not appear to change much with temperature and so could not be measured accurately. The temperature-dependence of the two main bands is complex. Between 60 and 100°K the low-energy band increases sharply in intensity, while the high-energy band decreases correspondingly. Above 110°K the situation reverses and the low-energy band decreases in intensity while the high-energy band grows. Both bands closely approximate symmetric Gaussians. The temperature-dependence of the intensity of these two bands is well-explained qualitatively by the existence of two kinds of minima on the adiabatic potential energy surface for the A state. However, predictions of the temperature-dependence of the two emission bands based on calculated adiabatic potential energy surfaces are not in quantitative agreement with the experimental results. Possible reasons for this are our lack of knowledge of precise values for the parameters which enter into the theory, namely the spin-orbit coupling constant, the exchange integral, and the electron lattice coupling constant. The possible role of the 3A1u state in emission is discussed briefly.
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