Good Vibrations: Calculating Excited State Frequencies Using Ground State Self-Consistent Field Models

△SCF methods have proven to be reliable computational tools for the assignment and interpretation of photoelectron spectra of isolated molecules. These results have increased the interest in △SCF techniques for electronic excited states based on improved algorithms that prevent convergence to ground states. In this work, one of these △SCF improved algorithms is studied to demonstrate its ability to explore the molecular properties for excited states. Results from △SCF calculations for a set of representative molecules are compared with results obtained using time-dependent density functional theory and single substitution configuration interaction method. For the △SCF calculations, the efficacy of a spin-purification technique is explored to remedy some of the spin-contamination presented in some of the SCF solutions. The obtained results suggest that the proposed projection-based SCF scheme, in many cases, alleviates the spin--contamination present in the SCF single determinants, and provides a computational alternative for the efficient exploration of the vibrational properties of excited states molecules.

∆SCF Dyson Orbitals and Pole Strengths from Natural Ionization Orbitals

The calculation of photoionization cross-sections can play a key role in spectral assignments using modeling and simulation. In this work, we provide formal relationships between pole strengths, which are proportional to the photoionization cross-section, and terms related to the Natural Ionization Orbital model for Delta-SCF calculations. A set of numerical calculations using the developed models is carried out. Pole strength values computed using the two approaches developed for Delta-SCF calculations demonstrate excellent agreement with an electron propagator theory model.

∆SCF Dyson Orbitals and Pole Strengths from Natural Ionization Orbitals

The calculation of photoionization cross-sections can play a key role in spectral assignments using modeling and simulation. In this work, we provide formal relationships between pole strengths, which are proportional to the photoionization cross-section, and terms related to the Natural Ionization Orbital model for Delta-SCF calculations. A set of numerical calculations using the developed models is carried out. Pole strength values computed using the two approaches developed for Delta-SCF calculations demonstrate excellent agreement with an electron propagator theory model.

Self-Consistent Mean Field Calculations of Polyelectrolyte-Surfactant Mixtures in Solution and upon Adsorption onto Negatively Charged Surfaces

Self-Consistent Mean-Field Calculations (SCF) have provided a semi-quantitative description of the physico-chemical behavior of six different polyelectrolyte-surfactant mixtures. The SCF calculations performed showed that both the formation of polymer-surfactant in bulk and the adsorption of the formed complexes onto negatively-charged surfaces are strongly affected by the specific nature of the considered systems, with the polymer-surfactant interactions playing a central role in the self-assembly of the complexes that, in turn, affects their adsorption onto interfaces and surfaces. This work evidences that SCF calculations are a valuable tool for deepening on the understanding of the complex physico-chemical behavior of polyelectrolyte-surfactant mixtures. However, it is worth noting that the framework obtained on the basis of an SCF approach considered an equilibrium situation which may, in some cases, be far from the real situation appearing in polyelectrolyte-surfactant systems.

Development of new auxiliary basis functions of the Karlsruhe segmented contracted basis sets including diffuse basis functions (def2-SVPD, def2-TZVPPD, and def2-QVPPD) for RI-MP2 and RI-CC calculations

Optimized auxiliary basis sets RI-post-SCF calculations are reported for the moderately diffuse def2-SVPD, def2-TZVPPD, and def2-QZVPPD basis sets.