1 Supporting Information The UV Absorption of Nucleobases: Semi-Classical Ab Initio Spectrum Simulations Mario Barbatti, Adelia J. A. Aquino, and Hans Lischka SUPPORTING INFORMATION........................................................................................................................... 1 I. FEATURES OF THE EXPERIMENTAL AND THEORETICAL SPECTRA...................................... 2 II. VERTICAL EXCITATIONS ........................................................................................................................ 3 A. ADENINE – CC2/TZVP................................................................................................................................. 3 B. ADENINE – CC2/TZVP-AUG ........................................................................................................................ 3 C. GUANINE – CC2/SVP ................................................................................................................................... 3 D. GUANINE – CC2/TZVP ................................................................................................................................ 4 E. GUANINE – CC2/TZVP-AUG ........................................................................................................................ 5 F. CYTOSINE –CC2/TZVP ................................................................................................................................ 5 G. CYTOSINE – CC2/TZVP-AUG....................................................................................................................... 6 H. THYMINE – CC2/TZVP ................................................................................................................................ 6 I. THYMINE – CC2/TZVP-AUG........................................................................................................................ 7 J. URACIL – CC2/TZVP ................................................................................................................................... 7 K. URACIL – CC2/TZVP-AUG........................................................................................................................... 8 III. OPTIMIZED GEOMETRIES AT CC2/TZVP LEVEL ....................................................................... 9 A. ADENINE ....................................................................................................................................................... 9 B. GUANINE....................................................................................................................................................... 9 C. CYTOSINE ..................................................................................................................................................... 9 D. THYMINE..................................................................................................................................................... 10 E. URACIL ....................................................................................................................................................... 10 REFERENCES ....................................................................................................................................................... 11