24989
The energy levels of 3 ^ 1 and 4 ^ 1 upper states of nitric acid are strongly interacting with those of the 9 ^ 3 , 6 ^ 2 , 5 ^ 19 ^ 1 and 7 ^ 18 ^ 1 dark states centered at 1288 . 899 , 1289 . 46 , 1341 . 05 and 1343 . 78 cm - 1 , respectively .
 nitric acid
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 nitric acid