▁is ▁ 0 . 2 6   e V . ▁▁ ▁+ ▁CO 2 ▁→ ▁Ar ▁+ ▁ ▁( y ield s ▁ 0 . 4 3 5   e V .) ▁ ▁van ▁der ▁Wa als ▁mole cules ▁Ne ut ral ▁arg on ▁atoms ▁bind ▁very ▁weak ly ▁to ▁other ▁neutral ▁atoms ▁or ▁mole cules ▁to ▁form ▁van ▁der ▁Wa als ▁mole cules . ▁These ▁can ▁be ▁made ▁by ▁expand ing ▁arg on ▁under ▁high ▁pressure ▁mixed ▁with ▁the ▁atoms ▁of ▁another ▁element . ▁The ▁expansion ▁happens ▁through ▁a ▁tiny ▁hole ▁into ▁a ▁vac u um , ▁and ▁results ▁in ▁cool ing ▁to ▁temper atures ▁a ▁few ▁degrees ▁above ▁absolute ▁zero . ▁ ▁At ▁higher ▁temper atures ▁the ▁atoms ▁will ▁be ▁too ▁ener get ic ▁to ▁stay ▁together ▁by ▁way ▁of ▁the ▁weak ▁London ▁disp ersion ▁forces . ▁The ▁atoms ▁that ▁are ▁to ▁combine ▁with ▁arg on ▁can ▁be ▁produced ▁by ▁ev ap oration ▁with ▁a ▁las er ▁or ▁altern atively ▁by ▁an ▁electric ▁dis charge . ▁The ▁known ▁mole cules ▁include ▁Ag Ar , ▁Ag 2 Ar , ▁Na Ar , ▁K Ar , ▁M g Ar , ▁Ca Ar , ▁Sr Ar , ▁Z n Ar , ▁C d Ar , ▁H g Ar , ▁Si Ar , ▁In Ar , ▁C Ar , ▁Ge Ar , ▁Sn Ar , ▁and ▁B Ar . ▁Si Ar ▁was ▁made ▁from ▁sil icon ▁atoms ▁derived ▁from ▁Si ( CH 3 ) 4 . ▁ ▁In ▁addition ▁to ▁the ▁very ▁weak ly ▁bound