Abstract
Photo-dissociation of NO2 plays a very important role in atmospheric chemistry, e.g., it affects the O3 level. In the present work, density-functional theory (DFT) and time-dependent density-functional theory (TD-DFT) were applied to investigate the detailed dissociation process of NO2. Initially, ultraviolet–visible spectra were predicted by using TD-DFT at the 6-311G (d,p) level with different exchange correlation functionals. Among the functionals studied, CAM-B3LYP was found to show the best agreement with the experimental data. Exogenous energy is required for the initial step of NO2 photo-dissociation, at which point a NO2 molecule is excited to the excited state. Then, a N⋯O bond-breaking process occurs spontaneously. In addition, the potential impact of atmospheric constituents including water and a solid carbonaceous surface on such reaction were further evaluated. The presence of water molecules can increase the activation energy, resulting in a lower photolysis frequency, while a carbonaceous surface may exhibit nearly no effect on NO2 photo-dissociation. The present study provides a novel strategy for furthering our understanding of the photochemical behavior of NO2.
Original language | English |
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Article number | 117559 |
Journal | Atmospheric Environment |
Volume | 230 |
DOIs | |
State | Published - Jun 1 2020 |
Externally published | Yes |
Funding
This work was financially supported by the National Natural Science Foundation of China (No. 21806037 ). Additional supports were from the Program for Guangdong Introducing Innovative and Entrepreneurial Teams ( 2017ZT07Z479 ). The authors would also thank Dr. Xingbao Wang from Taiyuan University of Technology for the technical support on the DFT calculation. This work was financially supported by the National Natural Science Foundation of China (No. 21806037). Additional supports were from the Program for Guangdong Introducing Innovative and Entrepreneurial Teams (2017ZT07Z479). The authors would also thank Dr. Xingbao Wang from Taiyuan University of Technology for the technical support on the DFT calculation.
Keywords
- Carbonaceous surface
- DFT/TD-DFT
- Nitrogen dioxide
- Photolysis
- Water