An unrestricted version of the algebraic diagrammatic construction (ADC) scheme of the polarization propagator in second order perturbation theory [UADC(2)] is derived via the intermediate state representation. The accuracy of the extended UADC(2)-x approach is evaluated by comparison of computed excitation energies of 11 medium-sized radicals with their corresponding experimental literature values and with excitation energies computed at equation-of-motion-CCSD (coupled clusters singles and doubles) level of theory. Overall, our numerical tests show that UADC(2)-x exhibits an averaged mean deviation in the excitation energies of only 0.3-0.4 eV compared to experimental gas phase data. It provides thus an alternative to coupled-cluster based approaches for the calculation of excited states of medium-sized open-shell molecules.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1063/1.3048877 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Supercontinuum generation in scintillator crystals.
Sci Rep
January 2025
Laser Research Center, Vilnius University, Saulėtekio Avenue 10, LT-10223, Vilnius, Lithuania.
We present a comparative experimental study of supercontinuum generation in undoped scintillator crystals: bismuth germanate (BGO), yttrium orthosilicate (YSO), lutetium oxyorthosilicate (LSO), lutetium yttrium oxyorthosilicate (LYSO) and gadolinium gallium garnet (GGG), pumped by 180 fs fundamental harmonic pulses of an amplified Yb:KGW laser. In addition to these materials, experiments in yttrium aluminium garnet (YAG), potassium gadolinium tungstate (KGW) and lithium tantalate (LT) were performed under identical experimental settings (focusing geometry and sample thickness), which served for straightforward comparison of supercontinuum generation performances. The threshold and optimal (that produces optimized red-shifted spectral extent) pump pulse energies for supercontinuum generation were evaluated from detailed measurements of spectral broadening dynamics.
View Article and Find Full Text PDFAb initio machine-learning unveils strong anharmonicity in non-Arrhenius self-diffusion of tungsten.
Nat Commun
January 2025
Institute for Materials Science, University of Stuttgart, D-70569, Stuttgart, Germany.
The knowledge of diffusion mechanisms in materials is crucial for predicting their high-temperature performance and stability, yet accurately capturing the underlying physics like thermal effects remains challenging. In particular, the origin of the experimentally observed non-Arrhenius diffusion behavior has remained elusive, largely due to the lack of effective computational tools. Here we propose an efficient ab initio framework to compute the Gibbs energy of the transition state in vacancy-mediated diffusion including the relevant thermal excitations at the density-functional-theory level.
View Article and Find Full Text PDFMeasurement of the Ge(d,n)As cross section from 2.1 MeV to 10 MeV.
Appl Radiat Isot
December 2024
Department of Medical Physics University of Wisconsin School of Medicine and Public Health, Madison, WI, 53705, USA. Electronic address:
This work reports experimental Ge(d,n)As cross sections producing Arsenic-71 (t = 65.3 h, 28% β), a potentially useful diagnostic radionuclide. Target stacks containing two Ge foils, a Ni monitor foil, and an Al degrader were irradiated with 5.
View Article and Find Full Text PDFTracking the structural change of the predissociating molecule near the transition state.
Nat Commun
January 2025
Department of Chemistry, KAIST, Daejeon, Republic of Korea.
Despite its profound significance, the molecular structural changes near the transition state, driven by the vibronic coupling, have remained largely unexplored, leaving a crucial aspect of chemical reactions shrouded in uncertainty. Herein, the dynamical behavior of the reactive flux on the verge of chemical bond breakage was revealed through the spectroscopic characterization of a large amplitude vibrational motion. Highly excited internal rotor states of S methylamine (CHND) report on the structural change as the molecule approaches the transition state, indicating that the quasi-free internal rotation is strongly coupled to the reaction coordinate as their energies near the maximum of the reaction barrier for the N-D chemical bond predissociation.
View Article and Find Full Text PDFSimulation of Ultrafast Excited-State Dynamics in Fe(II) Complexes: Assessment of Electronic Structure Descriptions.
J Chem Theory Comput
January 2025
HUN-REN Wigner Research Centre for Physics, P.O. Box 49, H-1525 Budapest, Hungary.
Article Synopsis
- The study evaluates different DFT and TD-DFT methods for simulating ultrafast excited-state dynamics in Fe(II) complexes.
- The research uses time-resolved X-ray emission spectroscopy data from specific iron complexes to benchmark simulation results between metal-to-ligand charge-transfer (MLCT) and metal-centered (MC) states.
- Findings suggest that the choice of DFT/TD-DFT method significantly impacts simulation accuracy, with B3LYP* and TPSSh performing best in matching experimental dynamics.
Want AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!