30024
The surprising finding is that alkali metals , in contrast to the rare gases , are efficiently Penning ionized upon excitation of the ( n = 2 ) - bands of the host droplets .
 Chemical: alkali metals
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: alkali metals