Solar Assisted Mitigation of Chloramphenicol and H Evolution Using CuNi Alloy Nanoparticles on h-BN Doped g-CN: A Comprehensive Approach Combining Synchrotron and DFT Analysis.

A simple one-step deposition-precipitation method was used to synthesize highly active and well-defined CuNi alloy bimetallic nanoparticles supported on h-BN/g-CN. The nanocomposite was applied for hydrogen gas evolution via seawater splitting and photocatalytic chloramphenicol (CHP) removal. Through TEM and synchrotron studies, the formation of CuNi alloy and uniform distribution of CuNi bimetallic nanoparticles on the h-BN/g-CN surface was observed.

Machine Learning-Assisted Mixed Quantum-Classical Dynamics without Explicit Nonadiabatic Coupling: Application to the Photodissociation of Peroxynitric Acid.

We have devised a hybrid quantum-classical scheme utilizing machine-learned potential energy surfaces (PES), which circumvents the need for explicit computation of nonadiabatic coupling elements. The quantities necessary to account for the nonadiabatic effects are directly obtained from the PESs. The simulation of dynamics is based on the fewest-switches surface-hopping method.

Investigation of the Effect of Solvents on the Synthesis of Aza-flavanone from Aminochalcone Facilitated by Halogen Bonding.

It has been recognized that CBr can give rise to a noncovalent interaction known as halogen bond (XB). CBr was found to catalyze, in terms of XB formation, the transformation of 2'-aminochalcone to aza-flavanone through an intramolecular Michael addition reaction. The impact of XB and the resulting yield of aza-flavanone exhibited a pronounced dependence on the characteristics of the solvent.

Semiclassical Dynamics on Machine-Learned Coupled Multireference Potential Energy Surfaces: Application to the Photodissociation of the Simplest Criegee Intermediate.

Determination of high-dimensional potential energy surfaces (PESs) and nonadiabatic couplings have always been quite challenging. To this end, machine learning (ML) models, trained with a finite set of data, allow accurate prediction of such properties. To express the PESs in terms of atomic contributions is the cornerstone of any ML based technique because it can be easily scaled to large systems.

Recent Advances in the Study of Negative-Ion Resonances Using Multiconfigurational Propagator and a Complex Absorbing Potential.

The transient resonances are a challenge to bound state quantum mechanics. These states lie in the continuum part of the spectrum of the Hamiltonian. For this, one has to treat a continuum problem due to electron-molecule scattering and the many-electron correlation problem simultaneously.

CBr catalyzed activation of α,β-unsaturated ketones.

We have shown here that weak interactions such as halogen bonding (XB) can be used to activate the carbonyl group of α,β-unsaturated ketones. Carbon tetrabromide (CBr) has been used as the sole reagent for the selective synthesis of flavanones and aza-flavanones from the corresponding 2'-hydroxy- and 2'-aminochalcones under metal-free and additive-free conditions. DFT calculations support the catalytic role of XB between the oxygen of chalcones and CBr in these reactions.

Investigation of negative-ion resonances using a subspace-projected multiconfigurational electron propagator perturbed with a complex absorbing potential.

The transient negative-ion resonances found in scattering experiments are important intermediates in many chemical processes. These metastable states correspond to the continuum part of the Hamiltonian of the projectile-target composite system. Usual bound-state electronic structure methods are not applicable for these.

An Electron Propagator Approach Based on a Multiconfigurational Reference State for the Investigation of Negative-Ion Resonances Using a Complex Absorbing Potential Method.

Negative-ion resonances are important metastable states that result from the collision between an electron and a neutral target. The course of many chemical processes in nature is often dictated by how an intermediate resonance state falls apart. This article reports on the development of an electron propagator (EP) based on a Hamiltonian perturbed by a complex absorbing potential (CAP) and a multiconfigurational self-consistent field (MCSCF) initial state to study these resonances.

A dinuclear [{(p-cym)Ru(II)Cl}2(μ-bpytz˙(-))](+) complex bridged by a radical anion: synthesis, spectroelectrochemical, EPR and theoretical investigation (bpytz = 3,6-bis(3,5-dimethylpyrazolyl)1,2,4,5-tetrazine; p-cym = p-cymene).

The reaction of the chloro-bridged dimeric precursor [{(p-cym)Ru(II)Cl}(μ-Cl)]2 (p-cym = p-cymene) with the bridging ligand 3,6-bis(3,5-dimethylpyrazolyl)-1,2,4,5-tetrazine (bpytz) in ethanol results in the formation of the dinuclear complex [{(p-cym)Ru(II)Cl}2(μ-bpytz˙(-))](+), [1](+). The bridging tetrazine ligand is reduced to the anion radical (bpytz˙(-)) which connects the two Ru(II) centres. Compound [1](PF6) has been characterised by an array of spectroscopic and electrochemical techniques.

Quantum dynamical investigation of the simplest Criegee intermediate CH2OO and its O-O photodissociation channels.

The singlet electronic potential energy surfaces for the simplest Criegee intermediate CH2OO are computed over a two-dimensional reduced subspace of coordinates, and utilized to simulate the photo-initiated dynamics on the S2 (B) state leading to dissociation on multiple coupled excited electronic states. The adiabatic electronic potentials are evaluated using dynamically weighted state-averaged complete active space self-consistent field theory. Quasi-diabatic states are constructed from the adiabatic states by maximizing the charge separation between the states.

Exploring Copper Oxide Cores Using the Projected Hartree-Fock Method.

Coupled binuclear copper oxide cores are present in the active sites of some of the very common metalloenzymes found in most living organisms. The correct theoretical description of the interconversion between the two dominant structural isomers of this core, namely, side-on μ-η(2):η(2)-peroxodicopper(II) and bis(μ-oxo)-dicopper(III), is challenging since it requires a method that can provide a balanced description of static and dynamic correlations. We investigate this problem using our recently developed projected Hartree-Fock method (PHF).

Projected quasiparticle theory for molecular electronic structure.

We derive and implement symmetry-projected Hartree-Fock-Bogoliubov (HFB) equations and apply them to the molecular electronic structure problem. All symmetries (particle number, spin, spatial, and complex conjugation) are deliberately broken and restored in a self-consistent variation-after-projection approach. We show that the resulting method yields a comprehensive black-box treatment of static correlations with effective one-electron (mean-field) computational cost.

Investigation of 2P Be- shape resonances using a quadratically convergent complex multiconfigurational self-consistent field method.

We develop, implement, and apply a quadratically convergent complex multiconfigurational self-consistent field method (CMCSCF) that uses the complex scaling theorem of Aguilar, Balslev, and Combes within the framework of the multiconfigurational self-consistent field method (MCSCF) in order to theoretically investigate the resonances originated due to scattering of a low-energy electron off of a neutral or an ionic target (atomic or molecular). The need to scale the electronic coordinates of the Hamiltonian as prescribed in the complex scaling theorem requires the use of a modified second quantization algebra suitable for biorthonormal spin orbital bases. In order to control the convergence to a stationary point in the complex energy hypersurface, a modified step-length control algorithm is incorporated.