Internal Pressure Measurements and Evaluation of External Molecular Vibrational Modes in the Liquid State

Bagley, E. B.; Nelson, T. P.; Chen, Sa; Barlow, J. W.

doi:10.1021/i160037a006

Cited by 23 publications

(1 citation statement)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The difference, of course, is affected by polar and hydrogen bond effects, as well as by molecular complexity and temperature as described in earlier work. 4 In the simplest cases such as cyclohexane the result, eq 2, follows if the total liquid state energy can be written as ETl = 5np + Sint + E?e + Ere (3) Here Enp represents the equilibrium energy of a molecule in a nonpolar liquid due to all the other molecules in the liquid. This energy is the result of the London dispersion forces between molecules.…”

Section: Introductionmentioning

confidence: 99%

Internal pressures of liquids and their relation to the enthalpies and entropies of mixing in nonelectrolyte solutions

Bagley¹,

Nelson²,

Scigliano³

1973

J. Phys. Chem.

Self Cite

View full text Add to dashboard Cite

For a number of liquids it has been shown previously that an unambiguous and physically reasonable free volume can be evaluated from internal pressure, P¡ = (dE/dV)T, measurements. The free volume is given as t>f = Vb = RT/{P + P¡), the b representing a quasilattice occupied volume. This approach to free volume has now been extended to solutions for which Pi of both the pure components and the mixtures are available. It is found experimentally that the occupied volume of the mixture, bm, is the mole fraction average of the occupied volume of the components. The excess entropy and excess enthalpy of mixing are shown experimentally to be given by -SE = R[xi In vn + X2 In ut2 -In urm] and EP = PimVm -xiPiiVi -X2P12V2 for all nonelectrolyte systems tested. Since internal pressure measurements for mixtures are rare, an equivalent approach is to compute P¡m from the Pi values for the pure components and the measured excess volumes, V6, through the relation Pim = {RT/(xiVn + 2 2 + V^)] -P.Excellent agreement is found between calculated and measured excess properties. As always with such solution calculations, the results are very sensitive to input data and hence more complicated methods than those proposed here would appear to be unwarranted.

show abstract

Section: Introductionmentioning

confidence: 99%

Internal pressures of liquids and their relation to the enthalpies and entropies of mixing in nonelectrolyte solutions

Bagley¹,

Nelson²,

Scigliano³

1973

J. Phys. Chem.

Self Cite

View full text Add to dashboard Cite

show abstract

Properties of liquids at the boiling point: Equation of state, internal pressure and vaporization entropy

Matyushov

Schmid

1994

Ber Bunsenges Phys Chem

View full text Add to dashboard Cite

Liquids at their respective boiling points are considered in the framework of factorization of density and temperature dependencies in the attraction term of the liquid equation of state. The factorization functions ~( q ) and a ( T ) are expressed through the vaporization enthalpy and the liquid packing density q. The latter is computed from the compressibility of the liquid with correcting for dipole-dipole interactions in the framework of the mean-spherical approximation. On the basis of the functional dependencies of ~ ( q ) and a ( T ) , derived from experimental data for a number of liquids, the applicability of equations of state to dense liquids at the boiling point can be analyzed. The function of q determined in this way relates the internal pressure to the cohesive energy. Upon decomposing the entropy of vaporization into the contributions from repulsions and attractions, the famous Trouton constant is shown to be largely determined by the unpacking of molecular hard spheres.

show abstract

Internal pressure behavior of polymers above and below the glass temperature

Bagley

Scigliano

1971

Polymer Engineering & Sci

Self Cite

View full text Add to dashboard Cite

It has been well established in the literature that the internal pressure, Pi = (∂E/∂V)T, of a polymer in the glassy state is about half the value expected from the behavior of the polymer just above the glass temperature, Tg. Consideration of this behavior in terms of a recent analysis of factors affecting internal pressures leads to the conclusion that the expression for the total energy of a glass must include a volume‐dependent stored energy term, a term not present above Tg. This stored energy could be associated with actual bond and segment deformations in the glassy state. Brittleness and solvent cracking behavior of glasses will be strongly dependent on this stored elastic energy which can be modified by altering the molding conditions under which the glass is formed.

show abstract

Internal Pressure Measurements and Evaluation of External Molecular Vibrational Modes in the Liquid State

Cited by 23 publications

References 5 publications

Internal pressures of liquids and their relation to the enthalpies and entropies of mixing in nonelectrolyte solutions

Internal pressures of liquids and their relation to the enthalpies and entropies of mixing in nonelectrolyte solutions

Properties of liquids at the boiling point: Equation of state, internal pressure and vaporization entropy

Internal pressure behavior of polymers above and below the glass temperature

Contact Info

Product

Resources

About