## H2O...HOH, water dimer complex

 H3 | O1 H5 - O2 | \ H4 H6

Tell me about the atomic charges, dipole moment, bond lengths, angles, bond orders,
molecular orbital energies, or total energy.
Tell me about the best Lewis structure.

## Atomic Charges and Dipole Moment

O1 charge=-0.810
O2 charge=-0.861
H3 charge= 0.424
H4 charge= 0.422
H5 charge= 0.417
H6 charge= 0.408
with a dipole moment of 2.74094 Debye

## Bond Lengths:

between O1 and H3: distance=0.975 ang___ between O1 and H4: distance=0.975 ang___
between O1 and H5: distance=1.902 ang___ between O2 and H5: distance=0.987 ang___
between O2 and H6: distance=0.972 ang___

## Bond Angles:

for H3-O1-O2: angle=105.7 deg___ for H4-O1-O2: angle=104.5 deg___
for H5-O2-O1: angle=5.469 deg___ for H6-O2-O1: angle=111.1 deg___

## Bond Orders (Mulliken):

between O1 and H3: order=0.881___ between O1 and H4: order=0.881___
between O1 and H5: order=-0.085___ between O2 and H5: order=0.843___
between O2 and H6: order=0.891___

## Best Lewis Structure

The Lewis structure that is closest to your structure is determined. The hybridization of the atoms in this idealized Lewis structure is given in the table below.

### Hybridization in the Best Lewis Structure

1. A bonding orbital for O1-H3 with 1.9995 electrons
__has 74.02% O 1 character in a s0.93 p3 hybrid
__has 25.98% H 3 character in a s orbital

2. A bonding orbital for O1-H4 with 1.9995 electrons
__has 74.02% O 1 character in a s0.93 p3 hybrid
__has 25.98% H 4 character in a s orbital

3. A bonding orbital for O2-H5 with 1.9994 electrons
__has 75.43% O 2 character in a sp2.88 hybrid
__has 24.57% H 5 character in a s orbital

4. A bonding orbital for O2-H6 with 1.9993 electrons
__has 72.88% O 2 character in a s0.89 p3 hybrid
__has 27.12% H 6 character in a s orbital

7. A lone pair orbital for O1 with 1.9983 electrons

8. A lone pair orbital for O1 with 1.9861 electrons
__made from a s0.74 p3 hybrid

9. A lone pair orbital for O2 with 1.9987 electrons

10. A lone pair orbital for O2 with 1.9981 electrons
__made from a p-pi orbital ( 99.95% p)

-With core pairs on: O 1 O 2 -

#### Donor Acceptor Interactions in the Best Lewis Structure

The localized orbitals in your best Lewis structure can interact strongly. A filled bonding or lone pair orbital can act as a donor and an empty or filled bonding, antibonding, or lone pair orbital can act as an acceptor. These interactions can strengthen and weaken bonds. For example, a lone pair donor->antibonding acceptor orbital interaction will weaken the bond associated with the antibonding orbital. Conversly, an interaction with a bonding pair as the acceptor will strengthen the bond. Strong electron delocalization in your best Lewis structure will also show up as donor-acceptor interactions.
Interactions greater than 20 kJ/mol for bonding and lone pair orbitals are listed below.

The interaction of the second lone pair donor orbital, 8, for O1 with the antibonding acceptor orbital, 71, for O2-H5 is 40.3 kJ/mol.

## Molecular Orbital Energies

The orbital energies are given in eV, where 1 eV=96.49 kJ/mol. Orbitals with very low energy are core 1s orbitals. More antibonding orbitals than you might expect are sometimes listed, because d orbitals are always included for heavy atoms and p orbitals are included for H atoms. Up spins are shown with a ^ and down spins are shown as v.

14 ----- 5.066

13 ----- 2.321

12 ----- 1.910

11 ----- -0.029

10 -^-v- -6.379

9 -^-v- -7.884

8 -^-v- -8.463

7 -^-v- -10.10

6 -^-v- -12.34

5 -^-v- -13.95

4 -^-v- -23.99

3 -^-v- -25.82

2 -^-v- -505.4

1 -^-v- -507.2

## Total Electronic Energy

The total electronic energy is a very large number, so by convention the units are given in atomic units, that is Hartrees (H). One Hartree is 2625.5 kJ/mol. The energy reference is for totally dissociated atoms. In other words, the reference state is a gas consisting of nuclei and electrons all at infinite distance from each other. The electronic energy includes all electric interactions and the kinetic energy of the electrons. This energy does not include translation, rotation, or vibration of the the molecule.

Total electronic energy = -152.9314603442 Hartrees