Identifying the Molecular Origin of Global Warming

A group increment scheme for infrared absorption intensities of greenhouse gases

“…In all of these models, the coefficients increase as more fluorines are added to a terminal or inner carbon. This is in agreement with previous studies, 8,9 which show that an increase in carbon-fluorine bonds results in a nonlinear increase in intensity for absorption within the IRW, and also with the observations of Blowers et al 15,16 Also, the coefficients for the groups containing oxygen are higher than the coefficients of the equivalent non-oxygenated groups. This agrees with observations made previously that fluorinated carbons situated next to an oxygen result in a larger absorption in the IRW or a larger radiative efficiency.…”

“…7 A large molecular radiative efficiency has been shown by Bera et al to arise when a molecule exhibits a large infrared absorption intensity within the IR window due to large dipole derivatives of highly polar bonds. 8 Moreover, HFCs and especially PFCs, tend to possess long atmospheric lifetimes since carbon-fluorine bonds are generally not very reactive with hydroxyl radicals in the atmosphere.…”

“…Finally, based on the analysis of the molecular origin of the strong absorption of radiation within the atmospheric IR window, 8 design strategies were devised to minimize an industrial molecule's radiative efficiency. 9 Due to the relatively shorter atmospheric lifetimes, HFEs have been recommended as alternatives for PFCs and HFCs.…”

“…This in combination with the carbon-fluorine vibrational stretch, which also occurs within the atmospheric IRW, makes perfluoroethers (PFEs) and HFEs very effective greenhouse gases. 8,9,12,[14][15][16][17][18] For fluorinated hydrocarbons and ethers, molecular structure greatly impacts its ability to absorb IR radiation. 9 It has been shown that by strategic distribution of fluorine atoms along the carbon framework, the infrared radiation absorption capacity can be reduced by a factor of two.…”

“…9 It has been shown that by strategic distribution of fluorine atoms along the carbon framework, the infrared radiation absorption capacity can be reduced by a factor of two. 8,9 Based on this knowledge, a group increment scheme for absorption intensities is proposed and investigated in the present study. The idea of a group increment scheme is analogous to…”