The electronic spectra of reaction products via photoexcited phenol/ammonia clusters (1:2–5) have been measured by UV-near-IR–UV ion dip spectroscopy. Compared with the electronic spectra of hydrogenated ammonia cluster radicals the reaction products have been proven to be (NH3)n−1NH4 (n=2–5), which are generated by excited-state hydrogen transfer in PhOH–(NH3)n. By comparing the experimental results with ab initio molecular orbital calculations at multireference single and double excitation configuration interaction level, it has been found that the reaction products (NH3)n−1NH4 (for n=3 and 4), contain some isomers.

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The lowest electronically excited state of small Na(H 2 O) n clusters have been investigated experimentally and theoretically. The excitation energy as determined by the depletion spectroscopy method drops from 16950 cm −1 for the sodium atom down to 9670 cm −1 when only three water molecules are attached to the Na atom. For larger clusters the absorption band shifts back towards higher energies and reaches 10880 cm −1 for n = 12. The experimental data are compared to quantum chemical calculations at the MP2 and MRSDCI levels. We found that the observed size-dependence of the transition energy is well reproduced by the interior structure where the sodium atom is surrounded by water molecules. The analysis of the radial charge distribution of the unpaired electron in these interior structures gives a new insight into the formation of the "solvated" electron.

Ab initio many-electron study for the low-lying states of the alkali hydride cations in the adiabatic representation Theoretical study of the electronic state and H-elimination reactions for solvated magnesium cluster ions

The picosecond time-resolved IR spectra of phenol/ammonia (1:3) cluster were measured by UV-IR-UV ion dip spectroscopy. The time-resolved IR spectra of the reaction products of the excited state hydrogen transfer were observed. From the different time evolution of two vibrational bands at 3180 and 3250 cm(-1), it was found that two isomers of hydrogenated ammonia radical cluster .NH(4)(NH(3))(2) coexist in the reaction products. The time evolution was also measured in the near-IR region, which corresponds to 3p-3s Rydberg transition of .NH(4)(NH(3))(2); a clear wavelength dependence was found. From the observed results, we concluded that (1) there is a memory effect of the parent cluster, which initially forms a metastable product, .NH(4)-NH(3)-NH(3), and (2) the metastable product isomerizes successively to the most stable product, NH(3)-.NH(4)-NH(3). The time constant for OH cleaving, the isomerization, and its back reaction were determined by rate-equation analysis to be 24, 6, and 9 ps, respectively.