Solvation spectra. Part 33.—Effect of pressure at various temperatures on the charge-transfer-to-solvent spectra of iodide in water and water+t-butyl alcohol mixtures

Abstract

The energy E_max of the absorption band maximum for the low-energy absorption band of the charge-transfer-to-solvent (c.t.t.s) spectrum of iodide increases rapidly with initial increase in pressure. The rate of increase then falls but eventually E_max increases linearly such that at constant temperature the straight line passes through the origin. With increase in temperature, E_max values follow a linear dependence at lower pressures but at 340 K they increase steadily with increase in pressure. When t-butyl alcohol is added, the dependence of E_max on pressure resembles that for iodide in water at a lower temperature. These changes are examined in terms of the effect of pressure on the energies of the c.t.t.s. ground and excited states.