27148
Fourier transform infrared ( FT - IR ) was used to detect the composition variation of foam film in the drainage process ; the vibration peak of OH for water molecule shifted from the 3390 cm ( - 1 ) ( being assigned to the bulk water integrated by hydrogen bonds ) to 3685 cm ( - 1 ) ( being assigned to the vibration of isolated water molecules ) for the ultrastable foam film after complete drainage , which agreed very well with the molecular simulation results .
 Chemical: OH; Chemical: hydrogen
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: OH; Chemical: hydrogen