1 9 3 - 9 5 - 1 ▁| } ▁ ▁Ar O * ▁is ▁also ▁formed ▁when ▁dio xygen ▁tra pped ▁in ▁an ▁arg on ▁matrix ▁is ▁subject ed ▁to ▁vac u um ▁ult rav io let . ▁It ▁can ▁be ▁detected ▁by ▁its ▁lum ines c ence : ▁O 2 ▁+ ▁h v ▁→ ▁ ▁+ ▁e − ; ▁ ▁+ ▁e − ▁→ ▁ 2 O * ; ▁O * ▁+ ▁Ar ▁→ ▁Ar O *. ▁Light ▁em itted ▁by ▁Ar O * ▁has ▁two ▁main ▁bands , ▁one ▁at ▁ 2 . 2 1 5   e V , ▁and ▁a ▁we aker ▁one ▁at ▁ 2 . 1 9 5   e V . ▁ ▁Arg on ▁sul f ide , ▁Ar S * ▁lum ines ces ▁in ▁the ▁near ▁inf ra red ▁at ▁ 1 . 6 2   e V . ▁Ar S ▁is ▁made ▁from ▁U V ▁ir rad i ated ▁O CS ▁in ▁an ▁arg on ▁matrix . ▁The ▁excited ▁states ▁last s ▁for ▁ 7 . 4 ▁and ▁ 3 . 5   μ s ▁for ▁spectrum ▁peak ▁and ▁band ▁respectively . ▁ ▁Tri atomic ▁van ▁der ▁Wa als ▁mole cules ▁Cl uster ▁mole cules ▁containing ▁dich lor ine ▁and ▁more ▁than ▁one ▁arg on ▁atom ▁can ▁be ▁made ▁by ▁forcing ▁a ▁ 9 5 : 5 ▁mixture ▁of ▁hel ium ▁and ▁arg on ▁and ▁a ▁trace ▁of ▁ch lor ine ▁though ▁a ▁no zz le . ▁Ar Cl 2 ▁exists ▁in ▁a