Two-Dimensional Fourier Transform Spectroscopy of Adenine and Uracil Using Shaped Ultrafast Laser Pulses in the Deep UV

We compare two-dimensional (2D) ultrafast Fourier transform spectroscopy measurements in the deep UV (262 nm) for adenine and uracil in solution. Both molecules show excited-state absorption on short time scales and ground-state bleaching extending for over 1 ps. While the 2D spectrum for uracil shows changes in the center of gravity during the first few hundred femtoseconds, the center of gravity of the 2D spectrum for adenine does not show similar changes. We discuss our results in light of ab initio electronic structure calculations.