Three procedures for incorporating higher level electronic structure data into reaction path dynamics calculations are tested. In one procedure, variational transition state theory with interpolated single-point energies, which is denoted VTST-ISPE, a few extra energies calculated with a higher level theory along the lower level reaction path are used to correct the classical energetic profile of the reaction. In the second procedure, denoted variational transition state theory with interpolated optimized corrections (VTST-IOC), which we introduced earlier, higher level corrections to energies, frequencies, and moments of inertia are based on stationary-point geometries reoptimized at a higher level than the reaction path was calculated. The third procedure, called interpolated optimized energies (IOE), is like IOC except it omits the frequency correction. Three hydrogen-transfer reactions, CH3 + H‘H → CH3H‘ + H (R1), OH + H‘H → HOH‘ + H (R2), and OH + H‘CH3 → HOH‘ + CH3 (R3), are used to test and validate the procedures by comparing their predictions to the reaction rate evaluated with a full variational transition state theory calculation including multidimensional tunneling (VTST/MT) at the higher level. We present a very efficient scheme for carrying out VTST-ISPE calculations, which are popular due to their lower computational cost. We also show, on the basis of calculations of the reactions R1−R3 with eight pairs of higher and lower levels, that VTST-IOC with higher level data only at stationary points is a more reliable dual-level procedure than VTST-ISPE with higher level energies all along the reaction path. Although the frequencies along the reaction path are not corrected in the IOE scheme, the results are still better than those from VTST-ISPE; this indicates the importance of optimizing the geometry at the highest possible level.

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Organic dyes have been synthesized which containing multiple electron donors (carbazole) and electron acceptors (rhodaniline-3-acetic acid) on triphenylamine (TPA). Photophysical, electrochemical, and theoretical computational methods have categorized these compounds. Nanocrystalline TiO2-based dye-sensitized solar cells (DSSCs) are fabricated using these dye molecules as light-harvesting sensitizers. The overall efficiency of sensitized cells is high (4.64%) as compared to a cis-di(thiocyanato)-bis(2,2′-bipyridyl)-4,4′-dicarboxylate ruthenium(II) (N3 dye)-sensitized device (7.83%) fabricated and measured under the same conditions. Both electron donor (carbazole) and acceptor (rhodaniline-3-acetic acid) play a key role in the increased efficiency. One carbazole and two rhodaniline-3-acetic acid-based dye appears to help convey the charge transfer from the excited dye molecules to the conduction band of TiO2, leading to a higher efficiency of the assembled devices using such a dye. Electrochemical impedance measurements support this dye’s effect on enhancing charge transfer of TiO2 (e−). Computation on this CTPAR2 compound also indicates a larger charge transfer efficiency in the electronically excited state.