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1.
After carrying out a systematic basis set convergence study, we evaluate several ground state potential energy surfaces of the Ar-N(2) van der Waals complex at the coupled cluster singles and doubles model including connected triples corrections. We use the aug-cc-pVXZ (X=5,Q,D) and the daug-cc-pVQZ basis sets augmented with a set of 3s3p2d1f1g (denoted 33211) and 3s3p2d2f1g (denoted 33221) midbond functions, respectively. aug-cc-pVTZ-33211 results were available in the literature. The aug-cc-pV5Z-33211 (daug-cc-pVQZ-33221) surface is characterized by a T-shaped minimum at R(e)=3.709 (3.701) A and of 99.01 (102.50) cm(-1), and a linear saddle point at 4.260 (4.257) A and D(e)=75.28 (79.73) cm(-1). These results are compared with the values provided by the semiempirical potentials available, and those of previous theoretical studies. The basis set convergence of the intermolecular potentials is also analyzed. From the potentials the rovibronic spectroscopic properties are determined. We study the basis set convergence of the rotational frequencies. The binding parameters that characterized the aug-cc-pVTZ-33211 surface are reasonable, but the surface is not good enough to evaluate the microwave spectra. The aug-cc-pVQZ-33211 basis set results considerably improve the triple zeta and are close to the aug-cc-pV5Z-33211. Considering the small differences between the quadruple and the quintuple zeta surfaces, the latter results can be expected to be close to convergence. At this level the differences with respect to the accurate experimental frequencies are in the order of 0.7%. In the case of the daug-cc-pVXZ-33211,33221 (X=5,Q,T,D) series, the convergence of the interaction energies with respect to basis set improvement is not so smooth. The errors in the frequencies obtained with the daug-cc-pVQZ-33221 basis set with respect to experiment are in the order of 0.4%. 相似文献
2.
Ab initio ground state potential energy surfaces are obtained from interaction energies calculated with the coupled cluster singles and doubles model including connected triples corrections [CCSD(T)] and the aug-cc-pVXZ (X=5,Q,T,D) basis sets augmented with two different sets of midbond functions (denoted 33221 and 33211). The aug-cc-pV5Z-33221 surface is characterized by a T-shaped 49.5 cm(-1) minimum at Re=3.38 Angstroms and a linear saddle point at 3.95 Angstroms with De=36.6 cm(-1). These results agree well with the values provided by the accurate semiempirical potentials available. The rovibronic spectroscopic properties are determined and compared to the available experimental data and previous theoretical results. We study the basis set convergence of the intermolecular potentials and the rotational frequencies. The aug-cc-pVTZ basis sets provide reasonable binding parameters, but seem not to be converged enough for the evaluation of the microwave spectra. The aug-cc-pVQZ basis sets considerably improve the triple zeta results. The differences between the results obtained with the aug-cc-pVTZ-33221 basis set surface and those with the aug-cc-pVQZ-33221 are smaller than those of the corresponding bases with the set of 33211 midbond functions. The aug-cc-pVQZ surfaces are close to the aug-cc-pV5Z, that are expected to be close to convergence. With our best surfaces the errors in the frequencies with respect to the accurate experimental results go down to 0.6%. 相似文献
3.
The thermal decomposition oftrans-3,5-di-tert-butyl-4-hydroxy-cinnamic acid (BHC) in the solid state, in aqueous solution and in solutions in organic solvents was studied in order to develop a preparative method for the synthesis of the monomeric antioxidant 3,5-di-tertbutyl-4-hydroxystyrene (BHS). Thermal methods of analysis showed that, during the solidstate decomposition of BHC, its decarboxylation was accompanied by desalkylation and polymerization of the styrenic decomposition products. BHC decarboxylation is aqueous solution was also accompanied by polymerization. A kinetic study of BHC decomposition in organic solvents by 1 H-NMR spectrometry revealed that only the decomposition of BHC in aprotic dipolar solvents such as dimethylsulphoxide and dimethylformamide, at temperatures lower than 150°C, could be used as a preparative method for the synthesis of BHS. The decarboxylation of BHC took place by zero-order kinetics through a mechanism involving the ionization of BHC in the aprotic dipolar solvent. The reaction rate increased drastically with increasing solvent polarity and in the presence of trace amounts of BHC sodium salt. Both monomeric antioxidants, i.e. BHS and BHC, may be used to obtain polymer-bound antioxidants, e.g. by melt-grafting onto polyethylene.
Zusammenfassung Für die Ausarbeitung eines Verfahrens zur Herstellung des monomeren Antioxidans 3,5-Di-terc-butyl-4-hydroxystyrol (BHS) wurde die thermische Zersetzung vontrans-3,5-Di-terc-butyl-4-hydroxyzimtsäure (BHC) im festen Zustand, in wäßriger Lösung und in Lösungen mit organischen Lösungsmitteln untersucht. Thermoanalytische Verfahren zeigten, daß bei der Feststoffzersetzung von BHC ihre Decarboxylierung durch Desalkylierung und durch Polymerisierung der Styrol-Zersetzungsprodukte begleitet wird. Auch die BHC-Decarboxylierung in wäßriger Lösung wurde durch Polymerisierung begleitet. Mittels 1H-NMR Spektroskopie angefertigte kinetische Studien der Zersetzung von BHC in organischen Lösungsmitteln zeigten, daß die Zersetzung von BHC nur in aprotischen dipolaren Lösungsmitteln, wie z.B. in Dimethylsulfoxid und Dimethylformamid und nur bei Temperaturen unterhalb von 150C als präparatives Verfahren zur Synthese von BHS geeignet ist. Die Decarboxylierung von BHC verlief nach einer Reaktionsordnung 0-ter Ordnung, am Mechanismus ist die Ionisierung von BHC im aprotischen dipolaren Lösungsmittel beteiligt. Die Reaktionsgeschwindigkeit wird mit steigender Lösungsmittelpolarität und in Gegenwart von Spuren von BHC-Natriumsalz drastisch angehoben. Beide monomeren Antioxidationsmittel, d.h. BHS und BHC, können verwendet werden, um Polymerbindungs-Antioxidationsmittel herzustellen, z.B. durch Schmelz-Auf-polymerisieren auf Polyethylen.相似文献
4.
5.
Raana Kashfi‐Sadabad Laura Gonzalez‐Fajardo Derek Hargrove Bahar Ahmadi Daniel Munteanu Sina Shahbazmohamadi Michael Jay Xiuling Lu 《Particle & Particle Systems Characterization》2019,36(4)
Nonspecific high‐energy radiation for treatment of metastatic ovarian cancer is limited by damage to healthy organs, which can be mitigated by the use of radiosensitizers and image‐guided radiotherapy. Gold (Au) and tantalum oxide (TaOx) nanoparticles (NPs), by virtue of their high atomic numbers, find utility in the design of bimetallic NP systems capable of high‐contrast computed tomography (CT) imaging as well as a potential radiosensitizing effect. These two radio‐dense metals are integrated into dendritic mesoporous silica NPs (dMSNs) with radial porous channels for high surface‐area loading of therapeutic agents. This approach results in stable, monodispersed dMSNs with a uniform distribution of Au on the surface and TaOx in the core that exhibits CT attenuation up to seven times greater than iodine or monometallic dMSNs without either TaOx or Au. Tumor targeting is assessed in a metastatic ovarian cancer mouse model. Ex vivo micro‐CT imaging of collected tumors shows that these NPs not only accumulate at tumor sites but also penetrate inside tumor tissues. This study demonstrates that after intraperitoneal administration, rationally designed bimetallic NPs can simultaneously serve as targeted contrast agents for imaging tumors and to enhance radiation therapy in metastatic ovarian cancer. 相似文献
6.
Gheorghe Munteanu 《Periodica Mathematica Hungarica》2007,55(1):97-112
In [Mu1] we underlined the motifs of holomorphic subspaces in a complex Finsler space: induced nonlinear connection, coupling
connections, and the induced tangent and normal connections. In the present paper we investigate the equations of Gauss, H-and A-Codazzi, and Ricci equations of a holomorphic subspace. We deduce the link between the holomorphic curvatures of the Chern-Finsler
connection and its induced tangent connection. Conditions for totally geodesic holomorphic subspaces are obtained.
Communicated by János Szenthe 相似文献
7.
In this paper we give a generalized form of the Schrödinger equation in the relativistic case, which contains a generalization of the Klein-Gordon equation. By complex Legendre transformation, the complex Lagrangian of electrodynamics produces a complex relativistic Hamiltonian H of electrodynamics, on the holomorphic cotangent bundle T′* M. By a special quantization process, a relativistic time dependent Schrödinger equation, in the adapted frames of (T′* M, H) is obtained. This generalized Schrödinger equation can be expressed with respect to the Laplace operator of the complex Hamilton space (T′*M, H). Finally, under some additional conditions on the proper time s of the complex space-time M and the time parameter t along the quantum state, by the method of separation of variables, we obtain two classes of solutions for the Schrödinger equation, one for the weakly gravitational complex curved space M, and the second in the complex space-time with Schwarzschild metric. 相似文献
8.
Alexandru?IonescuEmail author Gheorghe?Munteanu 《Mediterranean Journal of Mathematics》2017,14(4):163
The main purpose of the paper is the study of the total space of a holomorphic Lie algebroid E. The paper is structured in three parts. In the first section, we briefly introduce basic notions on holomorphic Lie algebroids. The local expressions are written and the complexified holomorphic bundle is introduced. The second section presents two approaches on the study of the geometry of the complex manifold E. The first part contains the study of the tangent bundle \(T_{\mathbb {C}}E=T'E\oplus T''E\) and its link, via the tangent anchor map, with the complexified tangent bundle \(T_{\mathbb {C}}(T'M)=T'(T'M)\oplus T''(T'M)\). A holomorphic Lie algebroid structure is emphasized on \(T'E\). A special study is made for integral curves of a spray on \(T'E\). Theorem 2.8 gives the coefficients of a spray, called canonical, obtained from a complex Lagrangian on \(T'E\). In the second part of section two, we study the holomorphic prolongation \(\mathcal {T}'E\) of the Lie algebroid E. In the third section, we study how a complex Lagrange (Finsler) structure on \(T'M\) induces a Lagrangian structure on E. Three particular cases are analysed by the rank of the anchor map, the dimensions of manifold M, and those of the fibres. We obtain the correspondent on E of the Chern–Lagrange nonlinear connection from \(T'M\). 相似文献
9.
Maria Cazacu Grigore Munteanu Angelica Vlad 《Journal of organometallic chemistry》2006,691(17):3700-3707
Two new polymeric structures containing ferrocene units along the chains, namely poly(silyl ester)s, have been synthesized and characterized: a geminal poly(silyl ester) (g-PSE) and one having a disiloxane spacer between the silyl ester groups (s-PSE). The condensation polymerization of AA/BB monomer systems in solution was used in both cases as preparation method involving a silicon-containing diol, (diphenylsilane diol or 1,3-bis(hydroxy)-tetramethyldisiloxane), and 1,1′-di(chlorocarbonyl)ferrocene. The polymers were investigated by differential pulse voltammetry in order to evaluate the redox behavior. Due to the presence of the silyl ester groups in the chain, these polymers are hydrolytically degradable. 相似文献
10.
Petre Ionita Vasile Dinoiu Cornel Munteanu Ioana Maria Turcu Victorita Tecuceanu Traian Zaharescu Eliza Oprea Cornelia Ilie Dan Anghel Gabriela Ionita 《Chemical Papers》2015,69(6):872-880
The rosemary extract was encapsulated in polyethylene or in covalently-based network gels. The covalent gels were obtained by the reaction of isocyanate end-capped polyethylene glycol (PEG) with β-cyclodextrin or glycerol. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay was used to evaluate the antioxidant activity (AA) of rosemary extract entrapped in polymeric structures and in ethanol or water solutions. The AA of the rosemary extract was determined using a DPPH radical for samples prepared in ethanol, and a water-soluble derivative, the sulphonated DPPH radical (DPPH-SO3Na), for the rosemary extract in water. Formulation of the rosemary extract in polymeric gels ensures a rapid release which determines the AA values similar to those in solution. 相似文献