Novel monolayer-boron (borophene) is a recent addition to the family of 2D materials. In particular, full surface hydrogenation of triangular borophene (borophane (BH)) to passivate empty p orbitals in boron is identified as producing a new stable 2D material that possesses direction-dependent Dirac cones similar to graphene. By a series of density functional theory (DFT) computations, we investigated the potential of single transition metal atoms supported on borophane with vacancies (the TM–BH system) as an efficient ORR/OER electrocatalyst for applications in renewable energy technologies. In TM–BH systems, the coupling of d-orbitals of the TM dopant with the p-orbitals of surrounding boron atoms results in an increase in the density of states near the Fermi-level generating active sites to facilitate the ORR/OER via an efficient four-electron transfer mechanism. Among the considered TM–BH systems, Fe–BH and Rh–BH were found to be promising ORR electrocatalysts with overpotentials (η^ORR) of 0.43 V and 0.47 V, respectively, whereas, for the OER, Rh–BH with 0.24 V has the smallest η^OER value followed by Co–BH (0.37 V), under the equilibrium electrode potential. These η^ORR and η^OER values indicate higher activities than the current most active ORR (Pt(111) (0.63 V)) and OER (rutile-type RuO₂ (0.37 V)) electrocatalysts.

Phosphorene suffers from instability under ambient condition, despite its potential to bridge the gap between graphene and two dimensional (2D) metal chalcogenides. We report effective exfoliation and stabilization of few layer phosphorene (FLP) in the presence of strongly interacting surfactants. Surfactants containing long hydrophobic chain and non-bulky charged head groups (CTAB) effectively exfoliate and stabilize FLP in water, which is consistent to our density functional theory prediction. Nuclear magnetic resonance (NMR) measurements are systematically employed to probe the interaction between surfactants and FLP. Retarded diffusion rate measured by 2D DOSY spectroscopy revealed the presence of noncovalently bonded CTAB over phosphorene. 2D NOESY spectroscopy further suggests the interdigitated arrangement of surfactants. Such a tight interaction impedes the ambient degradation rate of phosphorene by 70-80%. This work proposes a new insight into the control over ambient degradation of phosphorene without altering its intrinsic properties.

Electric dipole polarizability $\left({\alpha }_d\right)$ and the electric dipole moment (EDM) due to the electron-nucleus tensor-pseudotensor (T-PT) and the nuclear Schiff moment (NSM) interactions are accurately determined for ${}^{199}\mathrm{Hg}$. Relativistic many-body methods at different levels of approximations are employed to gain insights into the passage of the electron correlation effects in the evaluation of these properties. Significant changes in the results compared to previous calculations are observed. We estimate our final EDM results to be within 2% accuracy, which, in combination with the measured value of ${}^{199}\mathrm{Hg}$ EDM, yield limits on the T-PT coupling constant as $C_T<2.09\times {10}^{-9}$ and on the NSM as $S<1.45\times {10}^{-12}\left|e\right|{\text{fm}}^3$. Using these values, together with the latest nuclear structure and quantum chromodynamics calculations, we get limits for the strong CP-violating parameter as $|\overline{\theta }|<1.1\times {10}^{-9}$ and for the combined up- and down-quark chromo-EDMs as $|{\tilde{d}}_u-{\tilde{d}}_d|<2.8\times {10}^{-26}\left|e\right|\text{cm}$.

We employ the closed-shell perturbed relativistic coupled-cluster (RCC) theory developed by us earlier [ Phys. Rev. A 77, 062516 (2008)] to evaluate the ground-state static electric dipole polarizabilities ($\alpha$s) of several atomic systems. In this work, we have incorporated a class of higher-order many-body effects in our calculations that had not been taken into account in the above paper. We highlight their importance in improving the accuracies of $\alpha$s. We also calculate the ground state $\alpha$s of the inert gas atoms and several isoelectronic singly and doubly charged ions in order to make a comparative study of the trends of the correlation effects. Furthermore, we have developed a method to construct intermediate diagrams that are required for the computations of the unperturbed single and doubl coupled-cluster amplitudes. Our RCC results are compared with those of many-body perturbation theory at different orders to demonstrate the importance of higher-order correlation effects for the accurate determination of ($\alpha$s) of the systems that we have considered.