The phenomenon of electrochemiluminescence (ecl) during cathodic polarization of the np(1)-metals (AI, Ga and In) in peroxydisulfate solutions under different Values of pH is studied. It is proposed that the source of the light emission is a radiative deactivation of the singlet dioxygen, which is generated in the electrochemical system. A quantum-mechanical simulation of the free radical recombination reaction, during which the singlet dioxygen is generated, was carried out. It was determined that the HO2.- (OH)-O-.-recombination may proceed, under certain conditions, without a potential barrier, while the minimum potential barrier for the SO4.- - (O2H)-O-.-recombination (equals 27.1 kJ mol(-1)) is observed at an angle of attack 100 degrees.