Radiochemistry Division, Bhabha Atomic Research Centre, Mumbai 400085, India.
Spectrochim Acta A Mol Biomol Spectrosc. 2014 Jan 3;117:204-9. doi: 10.1016/j.saa.2013.07.104. Epub 2013 Aug 9.
PL and PAS studies were performed on uranyl compounds viz. uranium oxalate, uranium fluoride and ammonium uranyl fluoride. PL and PAS spectrum of ammonium uranyl fluoride is being reported for the first time. Ammonium uranyl fluoride is blue shifted with respect to uranyl fluoride, as a result of ammonium bonding. The vibronic separations were determined in the excited state and the ground state using excitation/PA spectra and emission spectra respectively. Fluorescence decay data could be fitted only with biexponential decay in all of these compounds indicating the presence of two different environments in these compounds. Low temperature luminescence leads to enhancement in emission intensity and lifetime value. The temperature dependence studies of average fluorescence lifetimes of ammonium uranyl are described in this paper. Based on this studies activation energy value for ammonium uranyl fluoride at which (3)∏ and (1)Σ potential surfaces will cross is calculated.
镎和 PAS 研究在铀的化合物上进行，如草酸铀、氟化铀和氟化铵铀。首次报道了氟化铵铀的光致发光（PL）和光声（PAS）光谱。由于铵键的存在，与氟化铀相比，氟化铵铀发生蓝移。通过激发/PA 光谱和发射光谱分别在激发态和基态确定了振子分离。在所有这些化合物中，荧光衰减数据只能用双指数衰减拟合，表明这些化合物中存在两种不同的环境。低温发光导致发射强度和寿命值的提高。本文描述了铵铀的平均荧光寿命的温度依赖性研究。基于此研究，计算了氟化铵铀的活化能值，在此能量下，（3）∏和（1）Σ势能面将相交。
