Long-lived excited states of He
*(2
1S and 2
3S)and He
**(in highly excited states), produced by impact of 20-200eV electrons were allowed to collide with H
2O and D
2O molecules. It was confirmed that ions H
+, HeH
+, OH
+ and H
2O
+ were produced by impact of He
* with H
2O. An ion produced by, a rearrangement chemi-ionization, HeH
+, was identified for the first time in the He
*+H
2O system. Another process, where He
** is ionized into He
+ by collision with H
2O, was also observed. These processes were discriminated by the difference in the threshold energies of the electrons used for exciting the helium atoms. The corresponding deuterated ions were observed when D
2O was used for the target.
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