title: Estimation of Radiative Efficiency of Chemicals with Potentially Significant Global Warming Potential.
abstract: Halogenated chemical substances are used in a broad array of applications, and new chemical substances are continually being developed and introduced into commerce. While recent research has considerably increased our understanding of the global warming potentials (GWPs) of multiple individual chemical substances, this research inevitably lags behind the development of new chemical substances. There are currently over 200 substances known to have high GWP. Evaluation of schemes to estimate radiative efficiency (RE) based on computational chemistry are useful where no measured IR spectrum is available. This study assesses the reliability of values of RE calculated using computational chemistry techniques for 235 chemical substances against the best available values. Computed vibrational frequency data is used to estimate RE values using several Pinnock-type models, and reasonable agreement with reported values is found. Significant improvement is obtained through scaling of both vibrational frequencies and intensities. The effect of varying the computational method and basis set used to calculate the frequency data is discussed. It is found that the vibrational intensities have a strong dependence on basis set and are largely responsible for differences in computed RE values.
authors.affiliation: U.S. Environmental Protection Agency, National Exposure Research Laboratory, Environmental Sciences Division, P.O. Box 93478, Las Vegas, Nevada 89193-3478, United States.
authors.forename: Don
authors.initials: D
authors.lastname: Betowski
authors.affiliation: U.S. Environmental Protection Agency, Office of Pollution Prevention and Toxics, Risk Assessment Division, 1200 Pennsylvania Avenue, N. W., Mail Code: 7408M, Washington, D.C. 20460, United States.
authors.forename: Charles
authors.initials: C
authors.lastname: Bevington
authors.affiliation: Material Measurement Laboratory, National Institute of Standards and Technology , 100 Bureau Drive, Stop 8320, Gaithersburg, Maryland 20899-8320, United States.
authors.forename: Thomas C
authors.initials: TC
authors.lastname: Allison
mesh_terms: D001272:Atmosphere / Q000737:chemistry*; D057232:Global Warming; D006846:Hydrocarbons, Halogenated; D008962:Models, Theoretical; D015203:Reproducibility of Results; D013472:Sunlight; D014732:Vibration
chemical_list: D006846:Hydrocarbons, Halogenated