19097
The experiments have picosecond time resolution and monitor the C - H stretch region of both the parent polyhalomethanes and their photolytically generated isomers .
 C, H, polyhalomethanes
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 C, H, polyhalomethanes