27615
We report and assign a number of NH3 - induced infrared absorption features of the pH2 host near 4150 cm ( - 1 ) , along with a cooperative transition that involves simultaneous vibrational excitation of a pH2 molecule and rotation - inversion excitation of NH3 .
 Chemical: NH3; Chemical: pH2; Chemical: pH2; Chemical: NH3
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: NH3; Chemical: pH2; Chemical: pH2; Chemical: NH3