<P> The quasi-static tunnelling (QST) is the ionization whose rate can be satisfactorily predicted by the ADK model, i.e. the limit of the PPT model when γ (\ displaystyle \ gamma) approaches zero . The rate of QST is given by </P> <Dl> <Dd> W A D K = C n ∗ l ∗ 2 6 π f l m E i (2 F (2 E i) 3 2) 2 n ∗ − m − 3 2 e − 2 3 F (2 E i) 3 2 (\ displaystyle W_ (ADK) = \ left C_ (n ^ (*) l ^ (*)) \ right ^ (2) (\ sqrt (\ frac (6) (\ pi))) f_ (lm) E_ (i) \ left ((\ frac (2) (F)) \ left (2E_ (i) \ right) ^ (\ frac (3) (2)) \ right) ^ (2n ^ (*) - m - (\ frac (3) (2))) e ^ (- (\ frac (2) (3F)) \ left (2E_ (i) \ right) ^ (\ frac (3) (2)))) </Dd> </Dl> <Dd> W A D K = C n ∗ l ∗ 2 6 π f l m E i (2 F (2 E i) 3 2) 2 n ∗ − m − 3 2 e − 2 3 F (2 E i) 3 2 (\ displaystyle W_ (ADK) = \ left C_ (n ^ (*) l ^ (*)) \ right ^ (2) (\ sqrt (\ frac (6) (\ pi))) f_ (lm) E_ (i) \ left ((\ frac (2) (F)) \ left (2E_ (i) \ right) ^ (\ frac (3) (2)) \ right) ^ (2n ^ (*) - m - (\ frac (3) (2))) e ^ (- (\ frac (2) (3F)) \ left (2E_ (i) \ right) ^ (\ frac (3) (2)))) </Dd> <P> As compared to W P P T (\ displaystyle W_ (PPT)) the absence of summation over n, which represent different above threshold ionization (ATI) peaks, is remarkable . </P>

What happens to the positively charged ions after dissociation