Partition Equilibrium Constants Research Articles

Partition functions and equilibrium constants for LiH and LiH +

Partition functions and equilibrium constants for the diatomic molecules LiH and LiH + are presented for temperatures T up to 40,000 K. The results are obtained by a direct sum of all electronic ground state rotational-vibrational levels whose energies are determined by solving the radial nuclear Schrödinger equation within the Born-Oppenheimer approximation.

A simple technique to estimate partition functions and equilibrium constants from Monte Carlo simulations

A combined Monte Carlo (MC) simulation-statistical mechanical treatment is proposed to calculate the internal partition function and equilibrium constant. The method has been applied to a number of one and multidimensional analytical functions. When sampling is incomplete, various factorization approximations for estimating the partition function are discussed. The resulting errors are smaller when the ratios of the partition functions are calculated (as in the determination of equilibrium constants) as opposed to the partition function itself.

Strategy for deciding between the use of single or biphasic systems as media for biocatalytic transformations using chemical equilibrium analysis

A theoretical model is derived to decide whether biphasic systems or single-phase aqueous systems are chosen as the media for microbial transformations. The yield ratio and product ratio at chemical equilibrium, which depend on the partition coefficients, equilibrium constants, activity coefficients and initial concentrations, are proposed as appropriate indices by the analysis of four common types of biochemical reaction under two extreme initial conditions.

Cyclic voltammetry and morphology of polyaniline-coated electrodes containing [Fe(CN)6]3–/4–ions

Three strategies for incorporation of [Fe(CN)6]3–/4– into polyaniline (PANI)-coated electrodes have been investigated: A, ion-exchange of [Fe(CN)6]3–/4– into pre-formed PANI-Cl- or PANI-SO4-coated electrodes; B, electropolymerisation of aniline from acidified K4[Fe(CN)6] or K3[Fe(CN)6]; and C, electropolymerisation of aniline from H4[Fe(CN)6]. Method A led to observable ion exchange into PANI-Cl or PANI-SO4 with acidified K4[Fe(CN)6] or K3[Fe(CN)6] solutions. The amount of film-confined [Fe(CN)6]3– corresponds to protonation of ca. 19% of the N atoms in PANI, but the response is not long-lived in hexacyanoferrate(III)-free electrolyte; a partition equilibrium constant of 220 ± 50 is measured. Method B effected [Fe(CN)6]3–/4– incorporation, but only when high concentrations of redox anion were present during PANI growth. The potential of the [Fe(CN)6]3–/4– couple in the polymer is shifted to +0.32 V (ΔEp= 40 mV) for PANI-[Fe(CN)6]3– compared with the standard potential +0.36 V vs. SCE in solution (at a freshly polished glassy carbon electrode). The oxidized form of the redox couple PANI-[Fe(CN)6]3– has a time-dependent voltammogram which collapses to a single broad wave at +0.32 V (ΔEp= 30 mV). The results also show that [Fe(CN)6]4– is exchanged more rapidly when the electrode potential of the film is cycled in HCl rather than in H2SO4, owing to ion-size considerations. Scanning electron microscopy (SEM) analysis on the PANI-[Fe(CN)6] films revealed a fibrous morphology indicative of a slower rate of growth than PANI-Cl. Method C also led to successful incorporation of [Fe(CN)6]3–/4–, whose presence was confirmed by fourier transform infrared (FTIR) spectroscopy.

A set of partition functions and equilibrium constants for 300 diatomic molecules of astrophysical interest

Developpements polynomiaux de fonctions de partition et de constantes d'equilibre de 300 molecules diatomiques et des atomes dependants, pour des temperatures de 1000 a 9000 K

Cell surface energy, contact angles and phase partition. I. Lymphocytic cell lines in biphasic aqueous mixtures

The surface energy of cells is the quantity which dominates certain physical interactions of cells such as adhesion to hydrophobic surfaces and phagocytosis. A linear relationship is derived relating the equilibrium constant obtained from phase partition in liquid-liquid systems with the surface energy difference obtained from contact-angle measurements. Using biphasic mixtures of Dextran and poly(ethylene glycol) in a medium of constant salt composition the expression is confirmed for transformed lymphocytic cell lines. The results demonstrate the importance of van der Waals' interactions in the phase-partition process, that phase partition can be used as a direct measure of cell surface hydrophobicity, and that the equilibrium constant of phase partition is directly related to the difference in the surface energy of the partitioned particle between the two phases.

Partition functions and equilibrium constants of some positive molecular ions

Partition functions and equilibrium constants have been determined for the positively charged molecular ions CH +, NH +, OH +, MgH +, AlH +, SiH +, SH +, HCl +, CaH +, C + 2, CN +, CO +, N + 2, NO +, SiO + and for the molecule FeH.

Pressure Dissociation and the Hydrogen Molecular Ion

The partition functions for the hydrogen molecular ion, with an estimate of pressure dependence included, have been calculated, using an extension of the Heftier-London theory. The partition functions have been used to evaluate the equilibrium constants and internal energies for H 2 + as a function of temperature and pressure. Tables of partition functions, equilibrium constants and internal energies have been given for T=3000 to 25 000°K and for pressures as high as 2 × 10 10 dyne/cm 2 .

Pressure Dissociation and Molecular Hydrogen

The partition functions for molecular hydrogen, with an estimate of pressure dependence included, have been calculated, using extension of Heitler-London theory to three electron system. These partition functions have been used to evaluate the equilibrium constants and internal energies for H 2 as a function of temperature and pressure. Tables of partition functions, equilibrium constants and internal energies have been given for T= I 000 ° to 15 000 ° K and for pressures as high as 7.7 × 10 9 dyn/cm 2 .

Partition Function Ratios and Equilibrium Constants for Oxygen-18 Exchange Reactions.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPartition Function Ratios and Equilibrium Constants for Oxygen-18 Exchange Reactions.S. C. Saxena, D. N. Bhatnagar, and S. RamaswamyCite this: J. Chem. Eng. Data 1962, 7, 2, 240–242Publication Date (Print):April 1, 1962Publication History Published online1 May 2002Published inissue 1 April 1962https://doi.org/10.1021/je60013a026RIGHTS & PERMISSIONSArticle Views53Altmetric-Citations3LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (325 KB) Get e-Alerts Get e-Alerts