8566
Observation of direct vibrational excitation in gas - surface collisions of CO with Au ( 111 ) : a new model system for surface dynamics .
 Chemical: CO; Chemical: Au
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: CO; Chemical: Au