## Al2 triplet state*

 Al1 - Al2
The multiplicity is 3.

## Atomic Charges and Dipole Moment

AL1 charge= 0.000
AL2 charge=-0.000
with a dipole moment of 0.00019 Debye

## Bond Lengths:

between AL1 and AL2: distance=2.779 ang___

## Bond Orders (Mulliken):

between AL1 and AL2: order=1.341___

## 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. The Lewis structure is built for the up and down electrons, separately. Note that the up and down structures can be very different.

### Hybridization in the Best Lewis Structure

#### Down Electrons

1. A bonding orbital for Al1-Al2 with 1.0000 electrons
__has 50.00% Al 1 character in a p-pi orbital ( 99.44% p 0.56% d)
__has 50.00% Al 2 character in a p-pi orbital ( 99.44% p 0.56% d)

2. A bonding orbital for Al1-Al2 with 1.0000 electrons
__has 50.00% Al 1 character in a p-pi orbital ( 99.44% p 0.56% d)
__has 50.00% Al 2 character in a p-pi orbital ( 99.44% p 0.56% d)

13. A lone pair orbital for Al1 with 0.9390 electrons

15. A lone pair orbital for Al2 with 0.9390 electrons

-With core pairs on:Al 1 Al 1 Al 1 Al 1 Al 1 Al 2 Al 2 Al 2 Al 2 Al 2 -

#### Up Electrons

11. A lone pair orbital for Al1 with 0.9434 electrons

15. A lone pair orbital for Al2 with 0.9434 electrons

-With core pairs on:Al 1 Al 1 Al 1 Al 1 Al 1 Al 2 Al 2 Al 2 Al 2 Al 2 -

## 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. Only the spin up electron orbital energies are given.

18 ----- -0.243

17 ----- -2.030
16 ----- -2.066

15 ----- -3.751 (pi)
14 -^--- -3.799 (pi)
13 -^--- -3.860 (sigma)

12 -^-v- -6.976

11 -^-v- -9.339

10 -^-v- -69.33 9 -^-v- -69.34

8 -^-v- -69.45 7 -^-v- -69.45

6 -^-v- -69.62 5 -^-v- -69.62

4 -^-v- -106.6 3 -^-v- -106.6

2 -^-v- -1500. 1 -^-v- -1500.

## 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 = -484.8168624427 Hartrees

* Our results agree with C.W. Bauschlicher, L. G. M. Pettersson J. Chem. Phys., 1987, 87(4), 2198-204, 2205-13, that the ground state is a triplet state (3Piu is reported to be lower than 3Sigma -g). Note that the ordering of the orbitals is like that for O2 and not N2!