Time-dependent density functional theory calculations of photoabsorption of fluorinated cyclic molecules in the vacuum ultraviolet region

Time-dependent density functional theory (TD-DFT) calculations of the photo absorption of molecules in the vacuum ultraviolet region have been performe d in order to aid in the design of transparent materials for use as photore sists for F-2 lithography (157 nm). The method including an empirical equat ion for correcting the calculated transition energy is described. We have u sed the TD-DFT approach to predict the photoabsorption of substituted benze nes, and cycloalkanes including norbornane. The calculations show that norb ornane is the best cycloalkane on which to start substitution studies. We r eport results on the mono-, di-, and tetra-fluorinated derivatives. The res ults show that the tetrafluoro-norbornanes have the lowest absorption in th e 157 nm range for the molecules that we studied.