We have investigated solvatochromic effects over a solvent series of increasing polarity on the prototype molecule pyrimidine as a solute species. The line shape profiles, obtained by a time-dependent approach based on quantum mechanical calculations performed over frames sampled from classical molecular dynamics trajectories, were directly compared to the available experimental bands. The multireference configuration interaction second-order perturbation (CI-MRPT2) calculations are in quantitative agreement with the experiment. The results also confirm how nonprotic solvents can be confidently modeled by continuous solvation models as the polarizable continuum model, whereas protic solvents, as water, require the inclusion of explicit solvent molecules to account for the effects of hydrogen bonds.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1021/jp509877q | DOI Listing |
J Phys Chem A
January 2025
Institute of Modern Physics, Shaanxi Key Laboratory for Theoretical Physics Frontiers, Northwest University, Xi'an, Shaanxi 710127, China.
The full-dimensional potential energy surface (PES) for the photodissociation of HNCS in the S(″) electronic state has been built up by the neural network method based on more than 48,000 points, which were calculated at the multireference configuration interaction level with Davidson correction using the augmented correlation consistent polarized valence triple-ζ basis set. It was found that two minima, namely, and isomers of HNCS, and seven stationary points exist on the S PES for the three dissociation pathways: HNCS(S) → H + NCS/HNC + S(D)/HN(Δ) + CS(Σ). The dissociation energies of two lowest product channels H + NCS and HNC + S(D) calculated on the PES are in good agreement with experimental results, validating the high accuracy of the PES.
View Article and Find Full Text PDFAcc Chem Res
January 2025
Department of Chemistry, Seoul National University, Seoul 151-747, South Korea.
ConspectusWhile traditional quantum chemical theories have long been central to research, they encounter limitations when applied to complex situations. Two of the most widely used quantum chemical approaches, Density Functional Theory (DFT) and Time-Dependent Density Functional Theory (TDDFT), perform well in cases with relatively weak electron correlation, such as the ground-state minima of closed-shell systems (Franck-Condon region). However, their applicability diminishes in more demanding scenarios.
View Article and Find Full Text PDFJ Phys Chem Lett
December 2024
Stanford PULSE Institute, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, United States.
Ni 2,2'-bipyridine complexes are commonly invoked intermediates in metallaphotoredox cross-coupling reactions. Despite their ubiquity, design principles targeting improved catalytic performance remain underdetermined. A series of Ni(bpy)(Ar)Cl (R = MeOOC, -Bu, R' = CH, CF) complexes were proposed to have multiconfigurational electronic structures on the basis of multiconfigurational/multireference calculations, with significant mixing of Ni → bpy metal-to-ligand charge transfer (MLCT) configurations into the ground-state wave function.
View Article and Find Full Text PDFPhys Chem Chem Phys
December 2024
Physics and Chemistry of Materials (T-1), Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
In the present work, we studied 27 FeH and 6 FeH electronic states using multireference configuration interaction (MRCI), Davidson-corrected MRCI (MRCI+Q), and coupled cluster singles doubles and perturbative triples [CCSD(T)] wavefunction theory (WFT) calculations conjoined with large quadruple- and quintuple- quality correlation consistent basis sets. We report their potential energy curves (PEC), energy related properties, spectroscopic parameters, and spin-orbit couplings. Dipole moment curves (DMC) and transition dipole moment curves (TDMC) of several low-lying electronic states of FeH and FeH are also introduced.
View Article and Find Full Text PDFJ Chem Phys
December 2024
Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas, Serrano 123, 28006 Madrid, Spain.
Photodissociation of the CH2Cl radical is investigated by using high-level multireference configuration interaction ab initio methods, including the spin-orbit coupling. All possible fragmentation pathways, namely, CH2Cl + hν → CH2 + Cl, HCCl + H, and CCl + H2, have been analyzed. The potential-energy curves of the ground and several excited electronic states along the corresponding dissociating bond distance of each pathway have been calculated.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!