Vibrational energy flow in adenosine triphosphate

Intermolecular vibrational energy transfer from H2O to adenosine triphosphate (ATP) molecules and intramolecular energy redistribution in ATP have been studied using the semiclassical Wentzel-Kramers-Brillouin procedure and quasiclassical trajectory calculations. The hydrogen bond interaction between the excited vibrational stretches of H2O (symmetric stretching mode in v = 1) and OH vibration of the γ-phosphate of the ground state ATP leads to efficient intermolecular energy flow, which is followed by intramolecular energy distribution in ATP. The phosphorus-oxygen chain functions as an efficient pathway for energy distribution to the ribose moiety and then ultimately to the terminal stretches of the adenine moiety, distributing most of the available energy to high-frequency OH, CH, and NH bonds on a sub-picosecond scale, while the hydrogen bond maintains its lifetime of ∼2 ps.