Vibrational dynamics of the water shell of DNA studied by femtosecond two-dimensional infrared spectroscopy

► Femtosecond two-dimensional infrared spectroscopy of hydrated DNA. ► Separation of NH stretching excitations of DNA base pairs and OH stretching excitations of water shell. ► NH stretching dephasing mainly by DNA fluctuations, minor role of water shell. ► Clear and selective evidence for slowing-down of water response in hydration shell compared to bulk water. ► Energy dissipation in hydration shell on similar time scale as in bulk water.