Linear absorption spectra of 8% HOD in in the OD stretch region at various thermodynamic state points corresponding to densities of 1.04, 1.00, 0.877, 0.693, and (left to right).
Maximum of the OD stretch absorption band of HOD vs the static dielectric constant of water. Our data are compared with those of Franck and Roth (Ref. 38).
Transient difference spectra of 6% HOD in at 573 K and 300 bars after excitation with a laser pulse centered at . Spectra are shown for different pump-probe delays. The full lines correspond to a fit of a model described in Fig. 5 to the measurements. The derived OD stretch lifetime is 4.6 ps.
Time dependent induced absorption signals at various probe frequencies for the same data set as shown in Fig. 3 (for clarity the traces are successively shifted along the vertical axis by a constant amount). The full lines correspond to a fit of a model (Fig. 5) to the data.
Kinetic model of the OD stretch relaxation of HOD in (adapted from Ref. 32). After exciting the level of the HOD molecule, the population decays to the ground state with a rate constant . The subsequent thermalization to the state is characterized by the rate constant . The cross sections , , and are identical but depend on the number of molecules reaching the thermalized ground state and, hence, vary with time. The cross section is time independent.
Normalized transient absorption signals probing the excited state of HOD in at various thermodynamic conditions. Full lines correspond to fits of the model presented in Fig. 5 to the data.
OD stretch relaxation rate constant of HOD vs the dielectric constant of water. The top axes indicate the average number of hydrogen bonds per water molecule determined from MD calculations (Ref. 40). Open symbols are data from Refs. 34 and 31, respectively. The solid line corresponds to a linear fit to the data points.
Vibrational energy levels (in ) of HOD in the gas phase (Ref. 41) and in liquid water (Ref. 42) at room temperature.
Comparison between experimental relaxation rate constants and model calculations. The solid line results from model A described in the text and dashed and dotted lines correspond to the individual rate constants of model A for the direct and the transition, respectively.
Relaxation times of the OD stretch vibration of HOD in .
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