(a) The potential curves for the ground and excited states of linear ICN− using multireference configuration interaction (MRCI) calculations without inclusion of the spin-orbit terms in the Hamiltonian. (b) Eigenvalues of the full Hamiltonian (including the spin-orbit terms). These will be referred to as the adiabatic potential curves for ICN− and are identical to those reported in Ref. 10 . The far right column shows the decomposition of the spin-orbit coupled electronic states in terms of the MRCI eigenstates. The color of the box indicates the adiabatic state that is being considered: (c) the ground state (plotted in black in (b)), (d) the second excited state (plotted in blue in (b)), and (e) the third excited state (plotted in red in (b)). These states are decomposed in terms of the (I + CN−) state (solid gray in (a)), the 2Π (I + CN−) state (dashed dark blue in (a)), and the (I− + CN) state (solid dark red in (a)).
ICN− potential-energy curves for the states relevant to visible photofragmentation. In panel (a), the solid curves show the adiabatic states, and are identical to the corresponding curves in Fig. 1(b) . The dashed curves show the diabatic states, and the blue dashed curve is identical to the solid dark red curve in Fig. 1(a) . The effect of CO2 solvation on the potentials is represented by a lowering of the potential when the majority of the charge is localized on the CN portion of the anion; this solvation is shown by the red dotted lines. The coupling between the two diabatic states is shown in panel (b).
Action spectra for the production of I− (red circles) and CN− (blue circles) photoproducts following photodissociation of ICN− between 430 and 650 nm. The left axis displays the I− intensities and the right axis the CN− intensities.
Photoproduct branching percentages following 2.5-eV (500-nm) excitation for ICN−(CO2) n for n = 0−18. The I− -based products are shown in red, CN−-based products are shown in blue, and ICN− -based products are shown in black. The distribution of solvents associated with each of the above photoproducts is available. 28
Calculated (B3LYP/aug-cc-pVTZ) potential energy of [NCCO2]− along a path corresponding to in-plane rotation of CN about its center-of-mass, showing the transition from the [NCCO2]− molecular form of the anion to the CN−(CO2) solvated anion. Important structures along this isomerization pathway are included. The E = 0 eV level corresponds to separated CN− and CO2.
Product branching percentages for (a) ICl−(CO2) n and (b) ICN−(CO2) n following absorption to the 2Π1/2 state at 1.7 eV (740 nm) and 2.5 eV (500 nm), respectively. The direct-dissociation product (I−) is shown in red, the charge-transfer product (Cl− or CN−) is shown in blue, and the recombination product (ICl− or ICN−) is shown in black. For ICN−(CO2) n , the dashed lines represent assigning the recombined products for n ≥ 12 to charge-transfer products for which the I atom has been retained via solvated I…[NCCO2]− complexes, as described in the text.
The average number of solvent molecules lost for the ICN−-based photoproducts as a function of parent cluster size, n, following 2.5-eV excitation of ICN−(CO2) n and ICN−(Ar) n (solid-green circles and solid-red triangles, respectively). The solid-gray line corresponds to the evaporation of all of the solvent molecules from the parent cluster.
The average number of CO2 molecules lost for the ICN−-based photoproducts as a function of parent cluster size following 2.5-eV (500-nm) and 2.1-eV (600-nm) excitation (solid-green circles and open-green triangles, respectively) of ICN−(CO2) n . The dashed horizontal lines show the average number of CO2 lost for larger clusters at these excitation energies assuming a 250-mV solvent binding energy. The gray diagonal line corresponds to the evaporation of all CO2 solvent molecules from the parent cluster.
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