▁from ▁ 2 0 0 ▁to ▁ 4 0 0   nm . ▁This ▁band ▁is ▁due ▁to ▁two ▁different ▁higher ▁states : ▁B 2 Π   →   A 2 Σ + ▁radi ates ▁over ▁ 2 1 0 – 4 5 0   nm , ▁and ▁E 2 Π   →   A 2 Σ + ▁is ▁between ▁ 1 8 0 ▁and ▁ 3 2 0   nm . ▁A ▁band ▁in ▁the ▁near ▁inf ra red ▁from ▁ 7 6 0 ▁to ▁ 7 8 0   nm . ▁ ▁Other ▁ways ▁to ▁make ▁Ar H ▁include ▁a ▁Pen ning - type ▁dis charge ▁t ube , ▁or ▁other ▁electric ▁dis charg es . ▁Yet ▁another ▁way ▁is ▁to ▁create ▁a ▁beam ▁of ▁Ar H + ▁( arg on ium ) ▁ ions ▁and ▁then ▁neutral ize ▁them ▁in ▁las er - ener g ized ▁ca es ium ▁v ap our . ▁By ▁using ▁a ▁beam , ▁the ▁lif et imes ▁of ▁the ▁different ▁energy ▁states ▁can ▁be ▁observed , ▁by ▁meas uring ▁the ▁profile ▁of ▁elect romagnet ic ▁energy ▁em itted ▁at ▁different ▁w avel ength s . ▁The ▁E 2 π ▁state ▁of ▁Ar H ▁has ▁a ▁radi ative ▁lifetime ▁of ▁ 4 0   ns . ▁For ▁Ar D ▁the ▁lifetime ▁is ▁ 6 1   ns . ▁The ▁B 2 Π ▁state ▁has ▁a ▁lifetime ▁of ▁ 1 6 . 6   ns ▁in ▁Ar H ▁and ▁ 1 7   ns ▁in ▁Ar D