Terahertz pump–probe of liquid water at 12.3 THz

Abstract

The dynamical complexity of the hydrogen-bonded water network can be investigated with intense Terahertz (THz) spectroscopy, which can drive the liquid into the nonlinear response regime and probe anharmonicity effects....

Reply to the ‘Comment on “Terahertz pump–probe of liquid water at 12.3 THz”’ by A. F. G. van der Meer, PCCP, 2022, 24, D1CP05216K

“…2 of ref. 1. In summary, not the refractive index variation as proposed in the comment, but an acoustic phonon as proposed in our paper 1 is in agreement with the experimental data.…”

“…Such large non-linear responses of liquid water at THz frequencies have been observed and reported independently by several other groups, as detailed in Table 1 of ref. 1. All these groups deduced quantitatively similar third-order non-linear responses of liquid water using different set-ups and radiation sources.…”

“…1 and 2 have been dissected into different contributions. As discussed before in detail, 1,2 a partial contribution is assigned to an unexpectedly large non-linear response, i.e., a large w 3 value. Such large nonlinear responses of liquid water at THz frequencies have been observed and reported independently by several other groups, as detailed in Table 1 of ref.…”

“…As shown in ref. 1, we can determine the thermal response of water when recording the THz pump-THz probe signals away from pulse overlap. For example, at pump probe delays t = AE6 AE 1 ps we find an increase in absorption (decrease in transmission) both during the pump macropulse and after it, with a timescale t th B 300 ms for water in the static cell (see the black curve in Fig.…”

“…The THz pump–THz probe signals in ref. 1 and 2 have been dissected into different contributions. As discussed before in detail, 1,2 a partial contribution is assigned to an unexpectedly large non-linear response, i.e.…”