Slow electron velocity-map imaging spectroscopy of cryogenically cooled TiOH anions is used to probe the simplest titania/water reaction, TiO + HO. The resultant spectra show vibrationally resolved structure assigned to detachment from the cis-dihydroxide TiO(OH) geometry based on density functional theory calculations, demonstrating that for the reaction of the anionic TiO monomer with a single water molecule, the dissociative adduct (where the water is split) is energetically preferred over a molecularly adsorbed geometry. This work represents a significant improvement in resolution over previous measurements, yielding an electron affinity of 1.2529(4) eV as well as several vibrational frequencies for neutral TiO(OH). The energy resolution of the current results combined with photoelectron angular distributions reveals Herzberg-Teller coupling-induced transitions to Franck-Condon forbidden vibrational levels of the neutral ground state. A comparison to the previously measured spectrum of bare TiO indicates that reaction with water stabilizes neutral TiO more than the anion, providing insight into the fundamental chemical interactions between titania and water.

Maximum overlap methods are effective tools for optimizing challenging ground-and excited-state wave functions using self-consistent field models such as Hartree-Fock and Kohn-Sham density functional theory. Nevertheless, such models have shown significant sensitivity to the user-defined initial guess of the target wave function. In this work, a projection operator framework is defined and used to provide a metric for non-aufbau orbital selection in maximum-overlap-methods. The resulting algorithms, termed the Projection-based Maximum Overlap Method (PMOM) and Projection-based Initial Maximum Overlap Method (PIMOM), are shown to perform exceptionally well when using simple user-defined target solutions based on occupied/virtual molecular orbital permutations. This work also presents a new metric that provides a simple and conceptually convenient measure of agreement between the desired target and the current or final SCF results during a calculation employing a maximum-overlap method.

Photoelectron spectra of Gd2O2 – obtained with photon energies ranging from 2.033 to 3.495 eV exhibit numerous close-lying neutral states with photon-energy-dependent relative intensities. Transitions to these states, which fall within the electron binding energy window of 0.9 and 1.6 eV, are attributed to one- or two-electron transitions to the ground and low-lying excited neutral states. An additional, similar manifold of electronic states is observed in an electron binding energy window of 2.1–2.8 eV, which cannot be assigned to any simple one-electron transitions. This study expands on previous work on the Sm2O– triatomic, which has a more complex electronic structure because of the 4f6 subshell occupancy of each Sm center. Because of the simpler electronic structure from the half-filled 4f7 subshell occupancy in Gd2O2 and Gd2O2 –, the numerous close-lying transitions observed in the spectra are better resolved, allowing a more detailed view of the changes in relative intensities of individual transitions with photon energy. With supporting calculations on numerous possible close-lying electronic states, we suggest a potential description of the strong photoelectron–valence electron interactions that may result in the photon-energy-dependent changes in the observed spectra.

High-resolution anion photoelectron spectroscopy of the ZrO3H2− and ZrO3D2− anions and complementary electronic structure calculations are used to investigate the reaction between zirconium dioxide and a single water molecule, ZrO20/− + H2O. Experimental spectra of ZrO3H2− and ZrO3D2− were obtained using slow photoelectron velocity-map imaging of cryogenically cooled anions, revealing the presence of two dissociative adduct conformers and yielding insight into the vibronic structure of the corresponding neutral species. Franck–Condon simulations for both the cis- and trans-dihydroxide structures are required to fully reproduce the experimental spectrum. Additionally, it was found that water-splitting is stabilized more by ZrO2 than TiO2, suggesting Zr-based catalysts are more reactive toward hydrolysis.

Donor-acceptor (D-A) materials, such as D-A co-crystals and D-A copolymers, can exhibit a wide range of unique photophysical properties with applications in next-generation optoelectronics. Identifying structure-function relationships to predict properties of materials from molecular features is a key challenge in the development of rational design principles. In this communication we present a novel metric for predicting the degree of charge transfer (DCT) in the S1 electronic state of D-A materials, using ground state orbital analysis. This metric computes the average of two quantities: (1) the degree of similarity between the highest occupied molecular orbital (HOMO) in the donor molecule and the D-A complex and (2) the degree of similarity between the lowest occupied molecular orbital (LUMO) in the acceptor molecule and the D-A complex. We demonstrate a linear relationship between this similarity metric and the DCT in the S1 state (HOMO → LUMO transition) for a data set of 31 D-A dimers. We discuss the integration of this novel orbital structure-function relationship into high-throughput screening methods and suggest best practices for choosing both molecular geometries and methods for computing the DCT.