Bond dipole moments in water and ammonia

Burnelle, Louis; Coulson, C. A.

doi:10.1039/tf9575300403

Cited by 46 publications

(11 citation statements)

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“…The dipole moment in gaseous water and in ice was calculated by computing the contributions of the two O-H bonds, JJ.B, and of the two lone pairs, JJ.L, to the total dipole moment of a H20 molecule, JJ.. oWe have used the SCF-MO for D= 00 and D=2.76 A for free water and ice, respectively, and the corresponding III) that due to our use of tetrahedral hybrids directed along tetrahedral directions the dipole moment JJ.L is very high, and to compensate this value, JJ.B results o~ opposite sign, in contradiction with the results obtamed for the free water molecule by Burnelle and Coulson 19 from the wavefunctions of Ellison and Shull. 5 Comparison of Burnelle and Coulson's results with ours also indicate that although the total dipole moment of water .is not very sensitive to changes in the geometry and m the wavefunctions, each of its contributions, JJ.L and JJ.B, vary appreciably with them.…”

Section: Dipole Momentmentioning

confidence: 74%

Molecular Orbital Study of the Hydrogen Bond in Ice

Weissmann

Cohan

1965

The Journal of Chemical Physics

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An SCF -MO-LCAO calculation for the four electrons involved in the straight hydrogen bond in ice is performed using a limited set of Slater-type orbitals. The energy of the four electrons plus the interaction between the "core potentials" is calculated as a function of the position of the proton along the line joining the oxygens. The energy of the hydrogen bond is obtained-8.2 kcal/mole-in good agreement with experiment. Electrostatic and delocalization contributions to the energy of the hydrogen bond are in excellent agreement with previous theoretical estimates. The potential energy for the motion of the proton results in a very asymmetric curve, with only one minimum. The dipole moment increases from 1.68 D for a free water molecule to 2.40 D thus confirming previous estimates.

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Section: Dipole Momentmentioning

confidence: 74%

Molecular Orbital Study of the Hydrogen Bond in Ice

Weissmann

Cohan

1965

The Journal of Chemical Physics

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“…As is well established there is a substantial movement of electron charge from the BF bonds into the vacant p z orbital as the out-of plane vibration occurs. Early calculations on H 2 O and NH 3 by Burnelle and Coulson emphasized the important contribution that variations in the lone pair contributions could make to the vibrational transition moments. In BF 3 this has the effect of reducing the apparent negative charge carried by the fluorine atom in the out-of-plane distortion …”

Section: Discussionmentioning

confidence: 99%

An ab Initio Study of the Complex BF₃·NF₃

Ford

Steele

1996

J. Phys. Chem.

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The structures and vibrational spectra of BF 3 , NF 3 , and the complex BF 3 ‚NF 3 have been computed at the SCF and MP2 levels using the 6-31G* basis set. It is proposed that the basis set superposition error be calculated at the MP structure but using the HF energies (RHF//MP) to avoid the enhancement of BSSE arising from the spurious LUMO of the ghost orbitals. With this treatment the binding energies at the MP2/ 6-31G* and MP2/6-31+G* levels are -8.58 and -7.36 kJ mol -1 , respectively. The molecular dipole derivatives with respect to Cartesian displacements of the nuclei in a Cartesian framework, oriented with respect to the bond direction, have been evaluated. It is demonstrated that these are very informative monitors of electron displacements on complexation. The deviations of the dipole gradients from the expectations of the first-order bond moment model are rationalized in terms of through space electron cloud interactions. It is proposed that conventional bond parameter models cannot give realistic visualizations of the charge flow during molecular vibrations. †

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“…On the assumption that the whole of the dipole moment of the water molecule originates in the 0-H bonds, the effective protonic charge is 1.5 x 10-10 e.s.u., which is the value used by Rowlinsonl2 in his treatment of sublimation energy and virial coefficients. However, a calculation of the orbital dipole moments by Burnelle and Coulson 13 shows that the major contribution to the molecular dipole moment comes from the lone pair electrons and that the contribution originating in the 0-H bond is about 1/10 of the total. This suggests that the formal charge of the proton may be as low as 0-16 x 10-1oe.s.u.…”

Section: Hydrogen Bonding and Frequency Shiftsmentioning

confidence: 99%

Hydrogen bonding of surface hydroxyl groups to physically adsorbed molecules

Frohnsdorff¹,

Kington²

1959

Trans. Faraday Soc.

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It is suggested that the marked difference which has been observed in the effects of adsorbed oxygen and nitrogen on the stretching frequency of surface OH groups of Aerosil silica is due to the difference in their quadrupole moments. This idea is supported by illustrative calculations. First, it is shown by a classical mechanical argument that small changes in the force component acting on the proton of an OH group in the OH direction produce approximately proportional changes in the OH stretching frequency. Then, for an adsorbed axially symmetric quadrupolar molecule, the contribution to the force component from the electrostatic interaction between its quadrupole moment and the proton of a surface OH group is considered ; it is seen to be a function of the effective protonic charge and of the position and orientation of the quadrupole. Although there is no detailed knowledge of these quantities, calculations based on a reasonable model of the surface OH group environment show that the observed frequency difference can be explained in terms of the proton-quadrupole interaction provided the effective protonic charge is not less than about 0.2 x 10-10 e.s.u.

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Bond dipole moments in water and ammonia

Cited by 46 publications

References 0 publications

Molecular Orbital Study of the Hydrogen Bond in Ice

Molecular Orbital Study of the Hydrogen Bond in Ice

An ab Initio Study of the Complex BF₃·NF₃

Hydrogen bonding of surface hydroxyl groups to physically adsorbed molecules

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Bond dipole moments in water and ammonia

Cited by 46 publications

References 0 publications

Molecular Orbital Study of the Hydrogen Bond in Ice

Molecular Orbital Study of the Hydrogen Bond in Ice

An ab Initio Study of the Complex BF3·NF3

Hydrogen bonding of surface hydroxyl groups to physically adsorbed molecules

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An ab Initio Study of the Complex BF₃·NF₃