Heat and free energy of formation of deuterium oxide

Rossini, Frederick D.; Knowlton, John W.; Johnston, H.L.

doi:10.6028/jres.024.020

Cited by 30 publications

(11 citation statements)

References 22 publications

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“…Several other values are available and they have been compared by Rossini et a1. 16 There seems to be little doubt that the N.B.S. value is the most reliable, and it alone will be used.…”

Section: Vaporization Of H20 and D20 At 0" Kmentioning

confidence: 99%

The difference in the intermolecular forces of H2O and D2O

Whalley¹

1957

Trans. Faraday Soc.

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The lattice energy of a compound at 0" K can be obtained from the heat of sublimation at 0" K, the zero-point energies due to the various intermolecular vibrations, and the difference between the crystal and the gas in the intramolecular zero-point energies. The difference in the lattice energies of isotopic molecules which have the same crystal structure is a good measure of the difference in their intermolecular forces. The lattice energy of H20 and the difference in lattice energies of H20 and D20 have been calculated from calorimetric and spectroscopic data. The lattice energy of D20 at 0" K is higher than that of H20 by 1-27 f 0.6 kJ mole-1. The difference is presumably due to the different intermolecular forces consequent on the anharmonic zero-point intramolecular vibrations, and the difference of dipole moments is probably the major contribution. This is the first clear evidence that isotopic molecules may have appreciably different intermolecular forces. The lattice energy of ice at 0" K is higher than is usually assumed because of the difference of zero-point energies between the solid and the vapour and it amounts to 56.0 f 0 7 kJ mole-*. Most of the assigned error is caused by the uncertainties in the distribution of intermolecular rotational frequencies.

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“…Several other values are available and they have been compared by Rossini et a1. 16 There seems to be little doubt that the N.B.S. value is the most reliable, and it alone will be used.…”

Section: Vaporization Of H20 and D20 At 0" Kmentioning

confidence: 99%

The difference in the intermolecular forces of H2O and D2O

Whalley¹

1957

Trans. Faraday Soc.

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“…The experimental heat of vaporization for H 2 O and D 2 O are 10.52 kcal/mol and 10.85 kcal/mol, respectively. 72,73 ECP CD models gave a heat of vaporization of 13.30 kcal/mol for H 2 O and 13.44 kcal/mol for D 2 O. It is not surprising that the liquid heat of vaporizations is also over-estimated when the heat capacities are over-estimated.…”

Section: Properties Of Liquid Water Investigated By the Ecp Potenmentioning

confidence: 99%

The strengths and limitations of effective centroid force models explored by studying isotopic effects in liquid water

Yuan

et al. 2018

The Journal of Chemical Physics

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The development of effective centroid potentials (ECPs) is explored with both the constrained-centroid and quasi-adiabatic force matching using liquid water as a test system. A trajectory integrated with the ECP is free of statistical noises that would be introduced when the centroid potential is approximated on the fly with a finite number of beads. With the reduced cost of ECP, challenging experimental properties can be studied in the spirit of centroid molecular dynamics. The experimental number density of HO is 0.38% higher than that of DO. With the ECP, the HO number density is predicted to be 0.42% higher, when the dispersion term is not refit. After correction of finite size effects, the diffusion constant of HO is found to be 21% higher than that of DO, which is in good agreement with the 29.9% higher diffusivity for HO observed experimentally. Although the ECP is also able to capture the redshifts of both the OH and OD stretching modes in liquid water, there are a number of properties that a classical simulation with the ECP will not be able to recover. For example, the heat capacities of HO and DO are predicted to be almost identical and higher than the experimental values. Such a failure is simply a result of not properly treating quantized vibrational energy levels when the trajectory is propagated with classical mechanics. Several limitations of the ECP based approach without bead population reconstruction are discussed.

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“…The calculation of the residual entropy was carried out by using our data along with the following values. The values of the molar enthalpy of vapourization, saturated vapour pressure, and the spectroscopic entropy of standard ideal gaseous state at 25°C were obtained from the works by Rossini and others ( 1940) and by Besley and Bottomley ( 1973)' The residual entropies were found to be 3.47 (Series I), 3.44 (Series 2), and 3•45 (Series 3) ± 0•4 I ] K -I mol-I, respectively, as shown in Table 11. These values are comparable in magnitude with those for H 2 0 ice.…”

Section: Residual Entropymentioning

confidence: 99%

Enthalpy Relaxation Phenomenon of Heavy Ice

1979

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The heat capacities of quenched and annealed heavy ice Ih were measured in the temperature range 14 to 300 K by an adiabatic calorimeter. A relaxational thermal anomaly was found at around 115K and this phenomenon was ascribed to the onset of deuteron ordering in the crystal. The average activation enthalpy of the relaxational process was determined to be (26±5) kJ mol–1. Residual entropies of the crystal were recalculated on the basis of the present heat-capacity data combined with the revised values for enthalpy of vapourization, saturated vapour pressure, and spectroscopic entropy. They are (3.47±0.41) J K–1 mol–1 for the quenched crystal and (3.44±0.41) J K–1 mol–1 for the crystal annealed at 102–106 K for 264 h. The characteristics and the origin of the anomaly are discussed in comparison with that of ordinary ice.

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Heat and free energy of formation of deuterium oxide

Cited by 30 publications

References 22 publications

The difference in the intermolecular forces of H2O and D2O

The difference in the intermolecular forces of H2O and D2O

The strengths and limitations of effective centroid force models explored by studying isotopic effects in liquid water

Enthalpy Relaxation Phenomenon of Heavy Ice

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