To look insight into the correlation between the fluorescence and SCO of (31)vacuum, temperature dependency of the fluorescence was measured for pure L23, while excited at 378 nm from 80-300 K. At 80 K, the emission spectra of L23 exhibited major peak having a shoulder located at around 487 and 513 nm, respectively (Fig. ). With increased temperature, the shoulder peak started vanishing, and the major peak was slightly red shifted at 497 nm at 300 K (Fig. ). The emission intensity was found to be 6.6 times lesser compared to that of at 80 K, indicating thermal quenching behavior. Then temperature dependency of fluorescence emission spectra of (31)vacuum