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Ions have a profound effect on the geometrical structure of liquid water and an aqueous environment is known to change the electronic structure of ions. Here we combine photoelectron spectroscopy measurements from liquid microjets with molecular dynamical and quantum chemical calculations to address the reverse question, to what extent do ions affect the electronic structure of liquid water? We study aqueous solutions of sodium iodide (NaI) over a wide concentration range, from nearly pure water to 8 M solutions, recording spectra in the 5 to 60 eV binding energy range to include all water valence and the solute Na+ 2p, I- 4d, and I- 5p orbital ionization peaks. We observe that the electron binding energies of the solute ions change only slightly as a function of electrolyte concentration, less than 150 ± 60 meV over an ∼8 M range. Furthermore, the photoelectron spectrum of liquid water is surprisingly mildly affected as we transform the sample from a dilute aqueous salt solution to a viscous, crystalline-like phase. The most noticeable spectral changes are a negative binding energy shift of the water 1b2 ionizing transition (up to -370 ± 60 meV) and a narrowing of the flat-top shape water 3a1 ionization feature (up to 450 ± 90 meV). A novel computationally efficient technique is introduced to calculate liquid-state photoemission spectra using small clusters from molecular dynamics (MD) simulations embedded in dielectric continuum. This theoretical treatment captured the characteristic positions and structures of the aqueous photoemission peaks, reproducing the experimentally observed narrowing of the water 3a1 feature and weak sensitivity of the water binding energies to electrolyte concentration. The calculations allowed us to attribute the small binding energy shifts to ion-induced disruptions of intermolecular electronic interactions. Furthermore, they demonstrate the importance of considering concentration-dependent screening lengths for a correct description of the electronic structure of solvated systems. Accounting for electronic screening, the calculations highlight the minimal effect of electrolyte concentration on the 1b1 binding energy reference, in accord with the experiments. This leads us to a key finding that the isolated, lowest-binding-energy, 1b1, photoemission feature of liquid water is a robust energetic reference for aqueous liquid microjet photoemission studies.

High-resolution carbon K-edge X-ray photoelectron, X-ray absorption, non-resonant and resonant Auger spectra are presented of gas phase trans-1,3-butadiene alongside a detailed theoretical analysis utilising nuclear ensemble approaches and vibronic models to simulate the spectroscopic observables. The resonant Auger spectra recorded across the first pre-edge band reveal a complex evolution of different electronic states which remain relatively well-localised on the edge or central carbon sites. The results demonstrate the sensitivity of the resonant Auger observables to the weighted contributions from multiple electronic states. The gradually evolving spectral features can be accurately and feasibly simulated within nuclear ensemble methods and interpreted with the population analysis. [ABSTRACT FROM AUTHOR]

Fourteen Slovak state-owned enterprises were studied, using published data and structured interviews with management. A novel methodology is used to assess SOE autonomy, effectiveness, accountability and governance. Variations in operating conditions reflect different government objectives and different ownership models. Mixed state-private firms performed more like competitive firms than did wholly state-owned SOEs. This information was fed into an assessment of Slovak SOEs’ compliance with the 2015 OECD Guidelines on SOE Corporate Governance. There are many differences between Slovak practice and the Guidelines. This may reflect a choice to favour government interests, rather than the OECD’s inclusion of a wider group of stakeholders. One cost is foregone efficiency gains. Another is the perception that the present highly opaque governance system hides corruption.

The aim of this article is to clarify the Balance-of-Payments (BOP)-constrained growth approach (Thirlwall's Law) in relation to the convergence theories. According to Thirlwall's Law, we determine the balance of payments equilibrium growth rate of an economy by the ratio of the income elasticities of the demand for exports and imports and the growth of foreign demand. Using Convergence Quadrants Diagram, we focused on an analysis of different phases of non-price convergence or divergence in the region of Central and Eastern Europe (CEE). The obtained results show that almost all countries of the CEE region grew at a higher rate than the one consistent with the BOP equilibrium. Moreover, it is proven that the convergence of the CEE region is unsustainable considering the lower ratio of income elasticities and increasing external debt. [ABSTRACT FROM AUTHOR]

Abstract: Triplet state mechanism of [2 + 2] photocycloaddition forming a cyclobutane ring from two ethylenes is investigated in the context of photocatalysis. High‐level ab initio calculations are combined with ab initio adiabatic molecular dynamics and ab initio metadynamics for rare events modeling. In a photocatalytic scheme, a reactant reaches the triplet state either via intersystem crossing (ISC) or triplet sensitization. The model system adopts a biradical structure, which represents energy intersection with the ground state. The system either completes cyclization or undergoes fragmentation into two olefinic units. The potential and free energy surfaces of the cyclobutane/ethylenes system are mapped with multireference approaches describing possible reaction pathways. To obtain a full picture of a double bond photoreactivity, ab initio adiabatic dynamical calculations were used to estimate reaction yields and to model the effects of excess energy. The potential use of density functional theory based approaches for [2 + 2] photocycloaddition was investigated for future simulations and design of realistic photocatalytic systems. Dynamical aspects of [2 + 2] photocycloaddition via a triplet state manifold are investigated by combining ab initio multireference methods and ab initio molecular dynamics and metadynamics. The reaction pathways are studied for a model system of two ethylenes forming a cyclobutane ring to provide a basis for further studies on design of photocatalytic systems. [ABSTRACT FROM AUTHOR]

The balance of payments can act as a constraint on the output growth rate, since it puts a limit on the growth of demand. The aim of this paper is to clarify the Post-Keynesian approach to the Balance-of-Payments-constrained growth by so-called Thirlwall Law. According to Thirlwall's Law, the balance of payments equilibrium growth rate of an economy can be determined by the ratio of the income elasticities of the demand for exports and imports and the growth of foreign demand. The theoretical concept of Balance-of-Payments constrained growth model is analyzed. Finally, its different modifications, especially multi-sector-version as an alternative approach that considers the structure of the economy are described. [ABSTRACT FROM AUTHOR]

We use molecular dynamics simulations to determine the melting point of ice Ih, for the polarizable POL3 water force field (Dang, L. X. J. Chem, Phys. 1992, 97, 2659). Simulations are performed on a slab of ice Ih, with two free surfaces at several different temperatures. The analysis of the time evolution of the total energy in the course of the simulations at the set of temperatures yields the melting point of the POL3 model to be Tm - 180 ± 10 K. Moreover, the results of the simulations show that the degree of hydrogen-bond disorder occurring in the bulk of POL3 ice is larger (at the corresponding degree of undercooling) than in ice modeled by nonpolarizable water models. These results demonstrate that the POL3 water force field is rather a poor model for studying ice and ice-liquid or ice-vapor interfaces. While a number of polarizable water models have been developed over the past years, little is known about their performance in simulations of supercooled water and ice. This study thus highlights the need for testing of the existing polarizable water models over a broad range of temperatures, pressures, and phases, and developing a new polarizable water force field, reliable over larger areas of the phase diagram. [ABSTRACT FROM AUTHOR]

The topical review focuses on calculating ionization energies (IE), or electronic polarons in quasi-particle terminology, in large disordered systems, e.g. for a solute dissolved in a molecular solvent. The simplest estimate of the ionization energy is provided by one-electron energies in the Hartree-Fock theory, but the calculated quantities are not accurate. Density functional theory as many-body theory provides a principal opportunity for calculating one-electron energies including correlation and relaxation effects, i.e. the true energies of electronic polarons. We argue that such a principal possibility materializes within the concept of optimally tuned range-separated hybrid functionals (OT-RSH). We describe various schemes for optimal tuning. Importantly, the OT-RSH scheme is investigated for systems capped with dielectric continuum, providing a consistent picture on the QM/dielectric boundary. Finally, some limitations and open issues of the OT-RSH approach are addressed.

Ions have a profound effect on the geometrical structure of liquid water and an aqueous environment is known to change the electronic structure of ions. Here we combine photoelectron spectroscopy measurements from liquid microjets with molecular dynamical and quantum chemical calculations to address the reverse question, to what extent do ions affect the electronic structure of liquid water? We study aqueous solutions of sodium iodide (NaI) over a wide concentration range, from nearly pure water to 8 M solutions, recording spectra in the 5 to 60 eV binding energy range to include all water valence and the solute Na + 2p, I - 4d, and I - 5p orbital ionization peaks. We observe that the electron binding energies of the solute ions change only slightly as a function of electrolyte concentration, less than 150 ± 60 meV over an ∼8 M range. Furthermore, the photoelectron spectrum of liquid water is surprisingly mildly affected as we transform the sample from a dilute aqueous salt solution to a viscous, crystalline-like phase. The most noticeable spectral changes are a negative binding energy shift of the water 1b 2 ionizing transition (up to -370 ± 60 meV) and a narrowing of the flat-top shape water 3a 1 ionization feature (up to 450 ± 90 meV). A novel computationally efficient technique is introduced to calculate liquid-state photoemission spectra using small clusters from molecular dynamics (MD) simulations embedded in dielectric continuum. This theoretical treatment captured the characteristic positions and structures of the aqueous photoemission peaks, reproducing the experimentally observed narrowing of the water 3a 1 feature and weak sensitivity of the water binding energies to electrolyte concentration. The calculations allowed us to attribute the small binding energy shifts to ion-induced disruptions of intermolecular electronic interactions. Furthermore, they demonstrate the importance of considering concentration-dependent screening lengths for a correct description of the electronic structure of solvated systems. Accounting for electronic screening, the calculations highlight the minimal effect of electrolyte concentration on the 1b 1 binding energy reference, in accord with the experiments. This leads us to a key finding that the isolated, lowest-binding-energy, 1b 1 , photoemission feature of liquid water is a robust energetic reference for aqueous liquid microjet photoemission studies.

The nature and stability of cetyltrimethylammonium bromide (CTAB) reverse micelles in chloroform formed above the critical micellar concentration at above- and subzero temperatures were examined by NMR and molecular dynamics simulations. The experiments showed that the supercooled micellar water pool becomes unstable upon cooling to relatively high temperatures (253 K), and smaller micelles are formed. Upon freezing at lower temperatures (233 K), micelles become completely frozen and remain intact in the solution. With an average hydrodynamic radius of approximately 1.3 nm, we estimate that the water pool contains approximately 50 water molecules, which is well below the onset of ice crystal formation. To support the experimental results, molecular dynamics simulations were used to model the structure of CTAB/water/chloroform reverse micelles of different sizes. The MD simulations show that the reverse micelles contain a water pool with bromide anions residing on its surface and their shape is nonspherical, especially in the case of larger water pools. Upon fast freezing, the mobility of the water molecules is suppressed, and the pool becomes more spherical.

We use molecular dynamics simulations to determine the melting point of ice I(h) for the polarizable POL3 water force field (Dang, L. X. J. Chem. Phys.1992, 97, 2659). Simulations are performed on a slab of ice I(h) with two free surfaces at several different temperatures. The analysis of the time evolution of the total energy in the course of the simulations at the set of temperatures yields the melting point of the POL3 model to be T(m) = 180 ± 10 K. Moreover, the results of the simulations show that the degree of hydrogen-bond disorder occurring in the bulk of POL3 ice is larger (at the corresponding degree of undercooling) than in ice modeled by nonpolarizable water models. These results demonstrate that the POL3 water force field is rather a poor model for studying ice and ice-liquid or ice-vapor interfaces. While a number of polarizable water models have been developed over the past years, little is known about their performance in simulations of supercooled water and ice. This study thus highlights the need for testing of the existing polarizable water models over a broad range of temperatures, pressures, and phases, and developing a new polarizable water force field, reliable over larger areas of the phase diagram., (© 2011 American Chemical Society)