16923
Here , we investigated vibrational population relaxation , P ( t ) , and orientational relaxation dynamics , r ( t ) , of free azide ion and contact ion pairs ( LiN3 , NaN3 , NH4N3 , MgN3 ( + ) , and CaN3 ( + ) ) in DMSO by IR pump - probe spectroscopy .
 azide, LiN3, NaN3, NH4N3, MgN3 ( + ), CaN3 ( + ), DMSO
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 azide, LiN3, NaN3, NH4N3, MgN3 ( + ), CaN3 ( + ), DMSO