Theoretical study of UV-Vis light absorption of some impurities in alkylbenzene type liquid scintillator solvents

Special chemical impurities may greatly decrease the light transparency of liquid scintillator (LS) solvents in the wavelength region 350–450 nm, which is of great importance to the neutrino experiments. The absorption wavelengths and oscillator strengths of two types of impurities (thiocarbonyls and nitrobenzene derivatives) and some similar compounds were calculated using TD-DFT in three scintillator solvents (toluene, pseudocumene, and linear alkyl benzene). Influences of these impurity molecules on LS solvent’s optical transmission in 350–450 nm were analyzed and compared with each other.