24762
Unique luminescent phenomena , for example , sharp energy level split and singlet - to - triplet transitions at room temperature , multiple discrete luminescence intensity periodic variation with polarization direction , are observed upon excitation with 980 nm linearly polarized laser .
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Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
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