| Abstract
| - Heterodyned 2D-IR, frequency resolved photon echo, and pump−probe spectroscopies were collected to studythe couplings and anharmonicities of cytidine and guanosine bases in DNA. Cytidine and guanosineanharmonicities were measured to be 9 and 14 cm-1, respectively. Strong cross-peaks were observed betweenthe guanosine (G) and cytosine (C) carbonyl stretches in the 2D-IR spectra of the self-complementaryoligonucleotide dG5C5 (5‘-GGGGGCCCCC-3‘). The spectra are interpreted in terms of inter- and intrastrandcouplings between the carbonyl modes, and an excitonic Hamiltonian, based on transition dipole coupling,was used to fit the 2D-IR spectra. The accuracy of this model is discussed in light of observed couplings tothe ring modes.
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