Coating of $$\hbox {C}_{60}$$ by para-$$\hbox {H}_2$$H2 and ortho-$$\hbox {D}_2$$D2: revisiting the solvation shell—CMMSE

The solvation of Buckminsterfullerene \(\hbox {C}_{60}\) by para-hydrogen and ortho-deuterium clusters has been modeled using a dedicated potential and path-integral molecular dynamics simulations at low temperature (2 K). The solvation shell obtained from the distribution of radial distances is found to be complete near 50 molecules, in agreement with recent mass spectrometry measurements. Deuteration increases the shell size by one, indicating a denser shell owing to less prominent vibrational delocalization for this heavier isotope.     

Electrical properties of the protonic conductor 1 mol% Y-doped $$ {\hbox{BaZr}}{{\hbox{O}}_{{3 - \delta }}} $$

Much attention has been paid to barium zirconates because their high protonic conductivity and chemical stability are excellent properties for solid electrolytes. However, most studies have focused on highly doped materials such as 10 or 20 mol% Y-doped barium zirconates. In this study, the bulk and the grain boundary electrical properties of 1 mol% Y-doped barium zirconate are investigated as a function of temperature, water partial pressure, and oxygen partial pressure. At low temperatures and in wet atmospheres, the bulk of the barium zirconate predominantly conducts protonic defects, whereas, at high temperatures and in dry conditions, it is mixed oxygen ionic and electron-hole conducting. In the grain boundary, the protonic conductivity is a few orders of magnitude lower than the protonic conductivity in the bulk. In this study, possible causes for the low protonic conduction at the grain boundaries are considered.     

A mathematical approach to chemical equilibrium theory for gaseous systems—III: \hbox {Q}_\mathrm{p}, \hbox {Q}_\mathrm{c}, and \hbox {Q}_{\mathrm{x}}

The reaction quotient Q can be expressed in partial pressures as $\hbox {Q}_\mathrm{P}$ or in mole fractions as $\hbox {Q}_{\mathrm{x}}$ . $\hbox {Q}_\mathrm{P}$ is ostensibly more useful than $\hbox {Q}_{\mathrm{x}}$ because the related $\hbox {K}_{\mathrm{x}}$ is a constant for a chemical equilibrium in which T and P are kept constant while $\hbox {K}_{\mathrm{P}}$ is an equilibrium constant under more general conditions in which only T is constant. However, as demonstrated in this work, $\hbox {Q}_{\mathrm{x}}$ is in fact more important both theoretically and technically. The relationships between $\hbox {Q}_{\mathrm{x}}$ , $\hbox {Q}_\mathrm{P}$ , and $\hbox {Q}_{\mathrm{C}}$ are discussed. Four examples of applications are given in detail.     

Schrödinger equations on $${\mathbb{R}^3 \times \mathcal{M}}$$ with non-separable potential

We consider the problem of defining the Schrödinger equation for a hydrogen atom on \({\mathbb{R}^3 \times \mathcal{M}}\) where \({\mathcal{M}}\) denotes an m dimensional compact manifold. In the present study, we discuss a method of taking non-separable potentials into account, so that both the non-compact standard dimensions and the compact extra dimensions contribute to the potential energy analogously to the radial dependence in the case of only non-compact standard dimensions. While the hydrogen atom in a space of the form \({\mathbb{R}^3 \times \mathcal{M}}\) , where \({\mathcal{M}}\) may be a generalized manifold obeying certain properties, was studied by Van Gorder (J Math Phys 51:122104, 2010), that study was restricted to cases in which the potential taken permitted a clean separation between the variables over \({\mathbb{R}^3}\) and \({\mathcal{M}}\) . Furthermore, though there have been studies on the Coulomb problems over various manifolds, such studies do not consider the case where some of the dimensions are non-compact and others are compact. In the presence of non-separable potential energy, and unlike the case of completely separable potential, a complete knowledge of the former case does not imply a knowledge of the latter.     

Equilibrium Chemistry in $${\text {BCl}}_3$$ BCl 3 – $${\text {H}}_2$$ H 2 –Ar Plasma

Plasma Chemistry and Plasma Processing - The approach, which was developed earlier for modeling chemical reactions in laser induced plasmas, is applied to radio-frequency discharge plasmas. The...     

Preparation,Structure, and Reactivity of ≡Si– $${\text{N}}^ \cdot$$ –H Radicals

A method is developed for the synthesis of Si– –H radicals on a silica surface and information is obtained by ESR and quantum chemical calculations of model systems on their structure and spectral (radiospectroscopic) characteristics. The reactivity of these radicals toward CO, H₂, and H₂=H₂ molecules is studied. The structure of the Si–HN– =O radical is analyzed, which is the product of CO addition. The kinetic and thermochemical characteristics of processes with the participation of synthesized radicals are determined.     

Sommerfeld’s fine structure constant approximated as a series representation in e and $$\pi $$

Sommerfeld in 1916 introduced the dimensionless fine structure constant, \(\alpha \), in to the context of atomic physics, in the course of working out the relativistic theory of the H atom, under the old quantum theory of Bohr. He was able to account for the fine structural detail of the atomic line spectrum of H by introducing this dimensionless constant which emerged naturally from his relativistic theory of the H atom. Since this time, the fine structure constant has emerged in several other contexts within experimental and theoretical physics. It has attained a status of being a mysterious number in physics that defies understanding as to its experimentally verified magnitude and identity. Being physically dimensionless, such a number invites a suggestion (or approximation) of its value in terms of mathematical constants in some formulation. Feynman most famously has conjectured that it might be possible to account for \(\alpha \) in some type of series or product expression in “e”, the base of natural logarithms, and “\(\pi \)” the familiar circular constant. Here we propose an infinite series in the product \(\mathrm{e} \cdot \pi \) that converges, within a few terms, to better than 9999 parts in 10,000 of the true value of \(\alpha \).     

Electrochemistry of Interaction Between Flavin Mononucleotide (FMN) and PM-17 as Antitumoral ε-Keggin Core Compound, \left[ {{\text{H}}_{ 2} {\text{Mo}}_{ 1 2}^{\text{V}} {\text{O}}_{ 2 8} \left( {\text{OH}} \right)_{ 1 2} \left( {{\text{Mo}}^{\text{VI}} {\text{O}}_{ 3} } \right)_{ 4} } \right]^{ 6- } at pH 7.5

In order to obtain a clue to the antitumor mechanism of $\left[ {{\text{Me}}_{ 3} {\text{NH}}} \right]_{ 6} \left[ {{\text{H}}_{ 2} {\text{Mo}}_{ 1 2}^{\text{V}} {\text{O}}_{ 2 8} \left( {\text{OH}} \right)_{ 1 2} \left( {{\text{Mo}}^{\text{VI}} {\text{O}}_{ 3} } \right)_{ 4} } \right]$ ·2H₂O (PM-17), the interaction of PM-17 with flavin mononucleotide (FMN) as a prosthetic group of the flavoprotein has been investigated by both polarographic analysis and isothermal titration calorimetry (ITC) technique at the physiological solution pH (7.5). The half-wave potential (?0.50 V vs. Ag/AgCl) of the d.c. polarogram for the quasi-reversible one-electron reduction of FMN was shifted by PM-17 toward a more positive potential with a resultant deviation from one-electron reduction to formally more than one-electron reduction waves. The PM-17 effect on the d.c. polarogram could be explained by a variety of FMN···(PM-17)_n (n > 0) aggregates with multiple conformations which was supported by the thermodynamic parameters (ΔH = ?29.7 kJ mol^?1, ΔS = ?28.2 J mol^?1 K^?1, ΔG = ?21.5 kJ mol^?1, and number of FMN in the binding with PM-17 (N) = 0.053 at 20 °C) estimated by the ITC technique. A large conformational change of the FMN domain by the FMN···(PM-17)_n aggregates is suggested to prevent the movement of the FMN centers into close proximity with nicotinamide adenine dinucleotide (NADH) with a resultant depression of the electron transport in NADH dehydrogenase.     

Approximation of the electron–proton mass ratio as a series in powers of $$\uppi $$

Eddington in 1923, first identified four dimensionless numbers, derived from combinations of the basic physical constants, which are known as the “Eddington constants”. In formulating these dimensionless numbers, Eddington, a leading physicist of his time, claimed that they are characteristic of the structure and dynamics of the Universe at large, on the microscopical scale and at the macroscopical scale. Recently, there has been suggested a possible way of accounting for the magnitude of one of these four dimensionless constants, indicated as the “fine structure constant”, \(\upalpha \), that first emerged from studies of the atomic line spectrum of H. A simple power series in the product \(\hbox {e}\cdot \uppi \) has been proposed, that fits the measured value of the fine structure constant to better than 9999 parts in 10,000. Following along these lines, the authors here propose a simple power series expansion in \(\uppi \) that agrees with the currently accepted measurement of the value of the electron–proton mass ratio (m/M), or \(\upbeta \), to better than 999 parts in 1000.     

SYNTHESIS AND STRUCTURE OF SALTS OF THE N,N′,N″-TRIS(4-(PHENYLDIAZENYL)PHENYL) IMIDOSULFITE ANION – AN ORGANIC ANALOGUE OF $$\mathbf{SO}_{\mathbf{3}}^{\mathbf{2}-}$$

Journal of Structural Chemistry - Reduction of 4,4′-bis-(phenyl azo)-diphenyl thiodiimide S(=N–C6H4–N=N–C6H5)2 (1) in tetrahydrofuran (ТHF) with potassium-intercalated...     

MHD mixed convection of $$ {\text{Al}}_{2} {\text{O}}_{3} $$ Al 2 O 3 –Cu–water hybrid nanofluid in a wavy channel with incorporated fixed cylinder

Journal of Thermal Analysis and Calorimetry - This study deals with mixed convection of $$ {\text{Al}}_{2} {\text{O}}_{3} $$ –Cu–water hybrid nanofluid in a wavy channel having a...     

Synthesis and Structure of Ruthenium Complexes $$\rm[{Ph_{3}PR]_2^+[RuCl_6]^{2-}}$$ (R = C2H5, CH=CHCH3, CH2CH=CHCH3, CH2OCH3), and $$\rm[{Ph_{3}PCH_2CH=CHCH_2{PPh_3}]_2^{2+}[Ru_2Cl_{10}O]^{4-}}$$[Ph3PCH2CH=CHCH2PPh3]22+[Ru2Cl10O]4−· 4H2O

Complexes \(\rm[{Ph_{3}PR]_2^+[RuCl_6]^{2-}}\), where R = C₂H₅ (I), CH=CHCH₃ (II), CH₂CH=CHCH₃ (III), and CH₂OCH₃ (IV), have been prepared by the reaction between ruthenium(III) chloride hydrate and triphenylorganylphosphonium chlorides in dimethylsulfoxide in the presence of hydrochloric acid. A hydrochloric acid solution of ruthenium(III) chloride hydrate when mixed with an aqueous solution of 2-butylene-1,4- bis(triphenylphosphonium dichloride) followed by recrystallization from dimethylsulfoxide results in complex \(\rm[{Ph_{3}PCH_2CH=CHCH_2{PPh_3}]_2^{2+}[Ru_2Cl_{10}O]^{4-}}\)· 4H₂O (V). According to X-ray diffraction data, phosphorus atoms in mono- and binuclear cations have slightly distorted tetrahedral coordination (CPC 105.54(13)°?113.00(8)°, P?C 1.758(9)?1.839(7) Å). In slightly distorted octahedral anions [RuCl₆]^2? of complexes I–IV, the Ru?Cl bond lengths vary in the range 2.3222(6)?2.340(2) Å; the cis-ClRuCl and trans-ClRuCl angles are 89.133(18)°–90.867(18)° and 179.53(13)°–180°, respectively. In the binuclear [(RuCl₅)₂O]^4? anion of complex V, RuCl₅ fragments are bonded by a bridging oxygen atom. The Ru–Cl bond lengths fall in the range 2.3375(8)?2.3957(8) Å; the Ru–O bond length is 1.7832(2) Å. The cis-ClRuCl, trans-ClRuCl, cis-ORuCl, and trans-ORuCl angles are 86.67(3)°?91.28(3)°, 174.60(3)°?174.83(3)°, 91.49(2)°?93.65(2)°, and 178.39(2)°, respectively. In crystals I–V, interionic hydrogen bonds Cl···H_cation (2.63?2.95 Å), Cl··· \({\rm{H}_{{H_2}O}}\) (2.35?2.79 Å), and H_cation···\({\rm{O}_{{H_2}O}}\) (1.72?1.93 Å) (for V) are found.     

The Phase Diagram and the Application for the Quaternary System K+, $$ {\text{NH}}{_4^{+}} $$//Cl−, $$ {\text{SO}}{_4^{2 -}} $$SO42-–H2O at 80.0 °C

The solubilities in the quaternary system K⁺, \( {\text{NH}}{_4^{+}} \)//Cl^?, \( {\text{SO}}{_4^{2-}} \)–H₂O and its two ternary subsystems NH₄Cl–KCl–H₂O, (NH₄)₂SO₄–K₂SO₄–H₂O at 80.0 °C were measured using the isothermal dissolution equilibrium method under atmospheric pressure, and the corresponding phase diagrams were plotted. In the phase diagram of the NH₄Cl–KCl–H₂O system, there are three crystalline zones, which correspond to (K_1?m,(NH₄)_m)Cl, ((NH₄)_n,K_1?n)Cl and the co-existence zone of (K_1?m,(NH₄)_m)Cl and ((NH₄)_n,K_1?n)Cl, respectively. In the phase diagram of the (NH₄)₂SO₄–K₂SO₄–H₂O system, there is only one crystalline zone for (K_1?t,(NH₄)_t)₂SO₄. In the phase diagram of the K⁺, \( {\text{NH}}{_4^{+}} \)//Cl^?, \( {\text{SO}}{_4^{2-}} \)–H₂O system, there are three crystal zones, which correspond to (K_1?t,(NH₄)_t)₂SO₄, (K_1?m,(NH₄)_m)Cl and ((NH₄)_n,K_1?n)Cl, respectively. According to the analysis and the calculations for the phase diagrams of the K⁺, \( {\text{NH}}{_4^{+}} \)//Cl^?, \( {\text{SO}}{_4^{2 -}} \)–H₂O system at 80.0 °C and 50.0 °C, this paper proposes a technological process. In the process, the (K_1?t,(NH₄)_t)₂SO₄ can be prepared at 80.0 °C and the ((NH₄)_n,K_1?n)Cl can crystallize out at 50.0 °C. The mass fraction of K₂SO₄ in product L₁ (K_1?t,(NH₄)_t)₂SO₄ (t?=?0.1465) is 88.48%. The composition of solid solutions in the K⁺, \( {\text{NH}}{_4^{+}} \)//Cl^?, \( {\text{SO}}{_4^{2 -}} \)–H₂O system was experimentally determined and then theoretical calculations about the process can be carried out.     

Thermodynamic Model for BiPO4(cr) and Bi(OH)3(am) Solubility in the Aqueous Na+–H+–\mathrm{H}_{2}\mathrm{PO}_{4}^{-}–\mathrm{HPO}_{4}^{2-}–\mathrm{PO}_{4}^{3-}–OH−–Cl−–H2O System

Prior to this study no data for the solubility product of BiPO₄(cr) or the complexation constants of Bi with phosphate were available. The solubility of BiPO₄(cr) was studied at 23±2?°C from both the over- and under-saturation directions as functions of a wide range in time (6–309 days), pH values (0–15), and phosphate concentrations (reaching as high as 1.0 mol?kg^?1). HCl or NaOH were used to obtain a range in pH values. Steady state concentrations and equilibrium were reached in <6 days. The data were interpreted using the SIT model. These extensive data provided a solubility product value for BiPO₄(cr) and an upper limit value for the formation of BiPO₄(aq). Because the aqueous system in this study involved relatively high concentrations of chloride, reliable values for the complexation constants of Bi with chloride were required to accurately interpret the solubility data. Therefore as a part of this investigation, existing Bi–Cl data were critically reviewed and used to obtain values of equilibrium constants for various Bi–Cl complexes at zero ionic strength along with the values for various SIT ion interaction parameters. Predictions based on these thermodynamic quantities agreed closely with our experimental data, the chloride concentrations of which ranged as high as 0.7 mol?kg^?1. The study showed that BiPO₄(cr) is stable at pH values <9.0. At pH values >9.0, Bi(OH)₃(am) is the solubility controlling phase. Reliable values for the Bi(OH)₃(am) solubility reactions involving Bi(OH)₃(aq) and $\mathrm{Bi}(\mathrm{OH})_{4}^{-}$ and the formation constants of these aqueous species are also reported.     

Density and Viscosity of a Ternary $$ x_{1} $$ 1-He xene(1) + $$ x_{2} $$ x2 1-Octene(2) + (1 − − x2) 1-Decene(3) Mi xture at High Temperatures and High Pressures

The density and viscosity of a ternary 1-hexene(1) + 1-octene(2) +1-decene(3) mixture (\( w_{1} = w_{2} = w_{3} = 0.333 \) weight fractions or \( x_{1} = 0.4257 \),\( x_{2} = 0.3190 \), \( x_{3} = 0.2553 \) mole fractions of 1-hexene, 1-octene, and 1-decene, respectively) have been simultaneously measured over the temperature range from (298 to 471) K and at pressures up to 196 MPa using a combined method of hydrostatic weighing and falling-body techniques, respectively. The combined expanded uncertainties of the density, pressure, temperature, concentration, and viscosity measurements at the 95% confidence level with a coverage factor of k = 2 are estimated to be (0.15 to 0.30)%, 0.05%, 0.02 K, 0.005 mol%, and (1.5 to 2.0)%, respectively. The measured densities and viscosities were used to calculate the excess molar volumes and viscosity differences. The excess molar properties (\( G_{\text{m}}^{\text{E}} , \, H_{\text{m}}^{\text{E}} , \, S_{\text{m}}^{\text{E}} \) and \( C_{\text{pm}}^{\text{E}} \)) and their pressure derivatives as a function of temperature and pressure have been calculated using the derived excess molar volumes. The measured viscosities were used to develop a theoretically based viscosity correlation model (Arrhenius–Andrade type equation) for the mixture.     

Vibratio nal assig nme nts,co nformatio nal a nalysis,a nd molecular structures of $$\left[ {\text{C}_{\text{ n}} \text{mim}} \right]\left[ {\text{NTF}_{\text{2}} } \right]$$C nmimNTF2 ( n = 2, 4, 6, a nd 8) imidazolium-based io nic liquids: a combi ned experime ntal a nd qua ntum chemical approach

This work is aimed at providing physical insights about the interactions of cations, anion, and ion pairs of four imidazolium-based ionic liquids of \(\left[ {{\text{C}}_{\text{n}} {\text{mim}}} \right]\left[ {{\text{NTF}}_{2} } \right]\) with varying alkyl chain lengths (n = 2, 4, 6, and 8) using both DFT calculations and vibrational spectroscopic measurements (IR absorption and Raman scattering) in the mid- and far regions. The calculated Mulliken charge distributions of \(\left[ {{\text{C}}_{\text{n}} {\text{mim}}} \right]\left[ {{\text{NTF}}_{2} } \right]\) ion pairs indicate that hydrogen-bonding interactions between oxygen and nitrogen atoms (more negative charge) on \(\left[ {{\text{NTF}}_{2} } \right]^{ - }\) anion and the hydrogen atoms (more positive charge) on the imidazolium ring play a dominating role in the formation of ion pair. Thirteen stable conformers of \(\left[ {{\text{C}}_{2} {\text{mim}}} \right]\left[ {{\text{NTF}}_{2} } \right]\) were optimized. According to our results, the strongest and weakest hydrogen bonds were existing in \(\left[ {{\text{C}}_{2} {\text{mim}}} \right]\left[ {{\text{NTF}}_{2} } \right]\) and \(\left[ {{\text{C}}_{8} {\text{mim}}} \right]\left[ {{\text{NTF}}_{2} } \right]\), respectively. A redshift of 290, 262, 258, and 257 cm^?1 has been observed for cations involving \(\left[ {{\text{C}}_{2} {\text{mim}}} \right]^{ + }\), \(\left[ {{\text{C}}_{4} {\text{mim}}} \right]^{ + }\),\(\left[ {{\text{C}}_{6} {\text{mim}}} \right]^{ + }\), and stretching vibrations of \({\text{C}}12{-}{\text{H}}3\), respectively. By increasing the chain length, the strength of hydrogen bonds decreases as a result of \({\text{C}}12{-}{\text{H}}3\) bond elongation and less changes are observed in stretching vibrations of \({\text{C}}12{-}{\text{H}}3\) compared to the free cations. To the best of our knowledge, this research is the first work which reports the far-IR of \(\left[ {{\text{C}}_{4} {\text{mim}}} \right]\left[ {{\text{NTF}}_{2} } \right]\), \(\left[ {{\text{C}}_{6} {\text{mim}}} \right]\left[ {{\text{NTF}}_{2} } \right]\), and \(\left[ {{\text{C}}_{8} {\text{mim}}} \right]\left[ {{\text{NTF}}_{2} } \right]\) and the mid-IR of \(\left[ {{\text{C}}_{8} {\text{mim}}} \right]\left[ {{\text{NTF}}_{2} } \right]\).     

Structural,Energetic, and Magnetic Properties of Ag$$_{}$$Rh$$_{m}$$m and Ag$$_{m}$$mRh$$_{}$$ Clusters with $$n \le 20$$n≤20 and $$m=0,1$$m=0,1

At first, a genetic algorithm in combination with either the parametrized density-functional tight-binding method or a Gupta-potential is used to determine the putative global minimum energy structures of mixed Ag\(_{n-m}\)Rh\(_{m}\) and Ag\(_{m}\)Rh\(_{n-m}\) clusters with \(n\le 20\) and \(m=0,1\). Subsequently, the resulting structures are re-optimized with a first-principles method. The results demonstrate that the exchange of a single silver atom by rhodium leads to compact core-shell-like structures with structural motifs well known from the Lennard-Jones system. For the systems of the present study, AgRh\(_{n-1}\) clusters retain their cube-based structural motif and the silver atoms typically avoid the corner positions within a cube if possible. Population analysis of both cluster systems shows that the total magnetic moment is mainly due to unpaired electrons on the rhodium atoms with a small ferro-magnetic contribution of the silver host in Ag\(_{n-1}\)Rh and virtually no contribution to the total magnetic moment from the single silver atom in AgRh\(_{n-1}\) clusters.