Knowledge Bank

We investigated how donor molecules' state density affect impulsive collisions by studing collisional energy transfer of vibrationally excited pyridine-d$5$ (donor) and H$2$O (bath), and the result was compared with experiments of pyridine:H$2$O, picoline:H$2$O and lutidine:H$2$O. Vibrationally excited pyridine-d$5$ was prepared by absorbing pulsed 266nm UV light from forth harmonic generator of a Nd:YAG laser. A tunable F-center laser with 0.0003 cm$\mathrm{<mrow\; data-mjx-texclass="ORD">-1</mrow>}$ resolution was used to probe individual H$2$O (000 to 001) rotational states. The population of each H$2$O rotational state was measured by time dependent transient IR absorption and the rate of single collision between pyridine-d$5$ and H$2$O was determined afterwards. The translational energy gain in H$2$O was obtained by Doppler-broadened linewidths for each rotational state and the rotational energy gain was measured by a population distribution of H$2$O rotational states with E between 1000 and 2000 cm$\mathrm{<mrow\; data-mjx-texclass="ORD">-1</mrow>}$. The probability distributions for the large energy transfer of pyridine-d$5$ and H$2$O was calculated and the result was compared with other donors and H$2$O.