Selected values of electric dipole moments for molecules in the gas phase

Nelson, Ralph D.; Lide, David R.; Maryott, A. A.

doi:10.6028/nbs.nsrds.10

Cited by 355 publications

(328 citation statements)

References 1 publication

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“…Different atomic charge electrostatic schemes (Mulliken, CHELPG and MK) gave similar dipole moments but overestimated the experimental result, 3.73 D, in the gas phase [39]. Among the standard methods to obtain charges and moments, it has been found that the MK results show an appreciable dependence on the orientation of the molecule [40].…”

Section: Atomic Charges Via Ab Initio Computationsmentioning

confidence: 90%

A New Force Field of Formamide and the Effect of the Dielectric Constant on Miscibility

Luz

Méndez-Maldonado

Núñez-Rojas

et al. 2015

J. Chem. Theory Comput.

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Current force fields underestimate significantly the dielectric constant of formamide at standard conditions. We present a derivation of an accurate potential for formamide, which functional form builds on the OPLS/AA force field. Our procedure follows the approach introduced by Salas et al. (J. Chem. Theory and Comp., Just accepted, 2015), that can use information from ab initio calculations and molecular dynamics simulations. We consider several strategies to derive the atomic charges of formamide. We find that the inclusion of polarization effects in the quantum mechanical computations is essential to obtain reliable force fields. By varying the atomic charges and the LennardJones parameters describing the dispersion interactions in the OPLS/AA force field, we derive an optimum set of parameters to obtain accurate results for the dielectric constant, surface tension and bulk density of liquid formamide in a wide range of thermodynamic states. We test the transferability of our parameters to investigate liquid/liquid mixtures. We have chosen as case study an equimolar mixture of formamide and hexan-2-one. This mixture involves two fluids with very different polar characteristics, namely, large differences in their dielectric constants and their performance as polar solvents. The new potential highlights the importance of the correct parametrization of the pure liquid phases to investigate liquid mixtures. Finally, we examine the microscopic origin of the observed inmiscibility between formamide and hexa-2-one.

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Section: Atomic Charges Via Ab Initio Computationsmentioning

confidence: 90%

A New Force Field of Formamide and the Effect of the Dielectric Constant on Miscibility

Luz

Méndez-Maldonado

Núñez-Rojas

et al. 2015

J. Chem. Theory Comput.

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“…For C 3 H 8 , the well-known dipole moment [55] and accurate low-density data [5] are sufficient to separate these effects with some confidence. The lowdensity data are reproduced within 0.02%.…”

Section: Discussion Of Individual Systemsmentioning

confidence: 99%

“…Dipole moments were taken from the compilation of Nelson et al [55] for propane (0.084 D; 1 D ≈ 3.335641 × 10 −30 C· m) and isobutane (0.132 D). A complication arises for molecules that exist in multiple conformations, each having a different dipole moment.…”

Section: Dipole Momentsmentioning

confidence: 99%

Method for Estimating the Dielectric Constant of Natural Gas Mixtures

Harvey

Lemmon

2005

Int J Thermophys

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A method has been developed for calculating the static dielectric constant (relative permittivity) of fluid mixtures, with an emphasis on natural gas. The dielectric constant is calculated as a function of temperature, density, and composition; the density is calculated with a fundamental mixture equation of state. Theory-based correlations were developed for the dielectric constant of all significant components of natural gas, including not only light hydrocarbons but also gases such as nitrogen and carbon dioxide. In many cases, these correlations took advantage of new, highly accurate data measured in cross capacitors. For mixtures, the pure-component values are combined as proposed by Harvey and Prausnitz; this produces better results than the traditional mixing rule.

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“…It is clearly seen that the b-component is 1000 times smaller than the a-component; therefore it can be neglected. To facilitate direct comparison of the theoretical equilibrium value with the experimental µ 0 dipole moments, 18,19,22 18 It is worth noting that Sobolev and co-workers estimated only the value of the b-component and derived an overall value of 0.44 D for the DM of VA. However, our analysis reveals that the b-component is negligible even after vibrational correction; therefore, the best experimental µ 0 dipole moment of VA is 0.43 ( 0.01 D, based on the measurements of Sobolev and coworkers.…”

Section: Iii1 Empirical Structuresmentioning

confidence: 99%

Semispectroscopic and Quantitative Structure−Property Relationship Estimates of the Equilibrium and Vibrationally Averaged Structure and Dipole Moment of 1-Buten-3-yne

2005

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Systematic quantum chemical calculations have been performed to obtain precise estimates of the equilibrium and vibrationally averaged molecular structure and electric dipole moment of vinylacetylene (VA, 1-buten-3-yne). Anharmonic (cubic and semi-diagonal quartic) MP2/cc-pVTZ force fields in normal coordinates were computed to account for anharmonic vibrational effects, including zero-point contributions to the rotational constants and the electric dipole moment. A simultaneous weighted least-squares structural refinement was performed, resulting in the best semispectroscopic estimate of the r e structure of VA. The refinement was based on experimentally measured ground-state rotational constants of two isotopologs of VA corrected to equilibrium values using MP2/cc-pVTZ vibration-rotation interaction constants and all-electron CCSD(T)/ aug-cc-pVTZ structural constraints. The semispectroscopic r e structure of VA agrees excellently with the high-level CCSD(T)/aug-cc-pVTZ ab initio structure. The most dependable, CCSD (

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Selected values of electric dipole moments for molecules in the gas phase

Cited by 355 publications

References 1 publication

A New Force Field of Formamide and the Effect of the Dielectric Constant on Miscibility

A New Force Field of Formamide and the Effect of the Dielectric Constant on Miscibility

Method for Estimating the Dielectric Constant of Natural Gas Mixtures

Semispectroscopic and Quantitative Structure−Property Relationship Estimates of the Equilibrium and Vibrationally Averaged Structure and Dipole Moment of 1-Buten-3-yne

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