Dirac-Like Fermions Anomalous Magneto-Transport in a Spin-Polarized Oxide 2D Electron System.

In a 2D electron system (2DES) the breaking of the inversion, time-reversal and bulk crystal-field symmetries is interlaced with the effects of spin-orbit coupling (SOC) triggering exotic quantum phenomena. Here, epitaxial engineering is used to design and realize a 2DES characterized simultaneously by ferromagnetic order, large Rashba SOC and hexagonal band warping at the (111) interfaces between LaAlO, EuTiO, and SrTiO insulators. The 2DES displays anomalous quantum corrections to the magneto-conductance driven by the time-reversal-symmetry breaking occurring below the magnetic transition temperature.

Large Nonlinear Transverse Conductivity and Berry Curvature in KTaO Based Two-Dimensional Electron Gas.

Two-dimensional electron gas (2DEG) at oxide interfaces exhibits various exotic properties stemming from interfacial inversion and symmetry breaking. In this work, we report large nonlinear transverse conductivities in the LaAlO/KTaO interface 2DEG under magnetic field. Skew scattering was identified as the dominant origin based on the cubic scaling of nonlinear transverse conductivity with linear longitudinal conductivity and 3-fold symmetry.

Constraints on Heavy Decaying Dark Matter from 570 Days of LHAASO Observations.

The kilometer square array (KM2A) of the large high altitude air shower observatory (LHAASO) aims at surveying the northern γ-ray sky at energies above 10 TeV with unprecedented sensitivity. γ-ray observations have long been one of the most powerful tools for dark matter searches, as, e.g.

How Many Surface Modes Does One See on the Boundary of a Dirac Material?

We present full expressions for the surface part of polarization tensor of a Dirac fermion confined in a half-space in 3+1 dimensions. We compare this tensor to the polarization tensor of eventual surface mode (which is a 2+1 dimensional Dirac fermion) and find essential differences in the conductivities in both Hall and normal sectors. Thus, the interaction with electromagnetic field near the boundary differs significantly in the full model and in the effective theory for the surface mode.

Implication of the Proton-Deuteron Radiative Capture for Big Bang Nucleosynthesis.

The astrophysical S factor for the radiative capture d(p,γ)^{3}He in the energy range of interest for big bang nucleosynthesis (BBN) is calculated using an ab initio approach. The nuclear Hamiltonian retains both two- and three-nucleon interactions-the Argonne v_{18} and the Urbana IX, respectively. Both one- and many-body contributions to the nuclear current operator are included.

Solvent effects on electron-driven proton-transfer processes: adenine-thymine base pairs.

Time-Dependent Density Functional Theory (TD-DFT) computations, with M05-2X and PBE0 functionals, have been employed for a detailed study of the Electron-Driven Proton-Transfer (PT) processes in an Adenine-Thymine Watson-Crick Base Pair in the gas phase and in solution, with the bulk solvent described by the polarizable continuum model. In the gas phase, TD-DFT computations predict that the Adenine → Thymine Charge Transfer (CT) excited state undergoes a barrierless PT reaction, in agreement with CC2 computations (S. Perun, A.

Harmonic and Anharmonic Vibrational Frequency Calculations with the Double-Hybrid B2PLYP Method: Analytic Second Derivatives and Benchmark Studies.

This work aims to provide reliable benchmark data on the accuracy of harmonic and anharmonic vibrational frequencies computed with the B2PLYP double-hybrid density functional method. The exchange-correlation contributions required for the B2PLYP analytical second derivatives are presented here, which allow for the effective calculation of harmonic frequency as well as cubic and semidiagonal quartic force fields. The latter, in turn, are necessary to compute the anharmonic vibrational frequencies with the perturbative approach (VPT2).

Accurate Harmonic/Anharmonic Vibrational Frequencies for Open-Shell Systems: Performances of the B3LYP/N07D Model for Semirigid Free Radicals Benchmarked by CCSD(T) Computations.

Impressive growth of computer facilities and effective implementation of very accurate quantum mechanical methods allow, nowadays, the determination of structures and vibrational characteristics for small- to medium-sized molecules to a very high accuracy. Since the situation is much less clear for open-shell species, we decided to build a suitable database of harmonic and anharmonic frequencies for small-sized free radicals containing atoms of the first two rows of the periodic table. The level of theory employed is the CCSD(T) model in conjunction with triple- and quadruple-ζ basis sets, whose accuracy has been checked with respect to the available experimental data and/or converged quantum mechanical computations.

Fully Integrated Approach to Compute Vibrationally Resolved Optical Spectra: From Small Molecules to Macrosystems.

A general and effective time-independent approach to compute vibrationally resolved electronic spectra from first principles has been integrated into the Gaussian computational chemistry package. This computational tool offers a simple and easy-to-use way to compute theoretical spectra starting from geometry optimization and frequency calculations for each electronic state. It is shown that in such a way it is straightforward to combine calculation of Franck-Condon integrals with any electronic computational model.

Integrated computational approach to vibrationally resolved electronic spectra: anisole as a test case.

A new general and effective procedure to compute Franck-Condon spectra from first principles is exploited to elucidate the subtle features of the vibrationally resolved optical spectra of anisole. Methods based on the density functional theory and its time-dependent extension for electronic excited states [B3LYP6-311+G(d,p) and TD-B3LYP6-311+G(d,p)] have been applied to geometry optimizations and harmonic frequency calculations. Perturbative anharmonic frequencies [J.

Integrated computational strategies for UV/vis spectra of large molecules in solution.

In recent years, the margin of interaction between computational chemistry and most branches of experimental chemistry has increased at a fast pace. The experimental characterization of new systems relies on computational methods for the rationalization of structural, energetic, electronic and dynamical features. In particular, novel computational approaches allow accurate estimates of molecular parameters from spectroscopic optical observables, giving rise to synergic interactions between experimentalists and theoretically-oriented chemists.