Photoionization dynamics of an aqueous iodide solution: the temperature dependence

Charge Transfer to Solvent Dynamics at the Ambient Water/Air Interface

“…The lifetime for these kinetics and phase changes are comparable to the ~0.2 ps suggested for the decay of the CTTS state to form the non-equilibrated [I 0 :e -] (aq) contact pair 4 and is consistent with the timescales reported from the transient fluorescence up-conversion measurements. 26 Therefore, it appears that the Smix polarisation is more sensitive to the CTTS state dynamics rather than the initial solvation of the un-equilibrated Figure 4a.…”

“…4 The 1320 nm PP and PS data shows that the initial signal is significantly larger relative to the signal after 3 ps compared to the same polarisation combinations at 800 nm. This is consistent with the rapidly blue-shifting absorption spectrum of the [I:e -] (aq) as it solvates, because 1320 nm is more resonant than 800 nm initially (see Figure 4a).…”

“…A particularly useful means of initiating CTTS reactions is photoexcitation to CTTS absorption bands of certain aqueous anions. The most studied of these has been the CTTS of iodide [2][3][4][5][6][7][8][9][10][11][12][13] and a schematic of the solvation dynamics are shown in Figure 1. However, these studies have focussed on the bulk dynamics, while arguably, electron transfer reactions are of most interest at interfaces, be it on an aerosol particle, on an interstellar dust-grain, or at a water/biomolecule interface.…”

Real-time observation of the charge transfer to solvent dynamics

“…The valence electrons of ground-state anions are bound by the nucleus, but the excited states are bound by solvent polarization 1 . The CTTS states of halides rapidly decay by ejection of an electron, which is then stabilized by solvation, leaving a neutral halogen atom behind [2][3][4][5][6][7][8][9][10][11][12][13][14] . Atomic anions are ideal for studies of the electron-transfer dynamics to the solvent, because the solute lacks internal (nuclear) degrees of freedom, such that the process of CTTSmediated electron ejection is entirely governed by the structure and motions of the solvation shell.…”

“…From the experimental point of view, there has been a huge effort aimed at observing the early-time dynamics of aqueous CTTS states using ultrafast transient absorption (TA) spectroscopy [1][2][3][4]15,22 and, more recently, ultrafast photoemission from liquid microjets 5,6 . However, these methods turned out to be exclusively sensitive to the electron signal, that is, the end product of the photodetachment process, because of its very large oscillator strength over a broad spectral range and the fact that the excited CTTS absorption is close to that of the solvated electron 5,6 .…”