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NH3 Molecule

Optimisation

Calculation Method RB3LYP
Basis Set CC-pVDZ
Final Energy (au) -56.55775873
RMS Gradient (au) 0.00000323
Point Group C3V
Bond Length 1.02
Bond Angle 105.7
         Item               Value     Threshold  Converged?
 Maximum Force            0.000006     0.000450     YES
 RMS     Force            0.000004     0.000300     YES
 Maximum Displacement     0.000004     0.001800     YES
 RMS     Displacement     0.000009     0.001200     YES

Media:IROBINSON_AMMONIA_OPTIMISATION.LOG

Interactive Diagram

ammonia

Vibrations

Number of Modes 6
Degenerate Modes (2&3) (5&6)
Bending Vibrations 1,2,3
Stretching Vibrations 4,5,6
Highly Symmetric Mode 4
Umbrella Mode 1
Number of bands in an experimental spectrum 4

Charge

Nitrogen -1.048
Hydrogen 0.349

Nitrogen is expected to have a negative partial charge whilst hydrogen is expected to have a positive partial charge, because nitrogen is more electronegative than hydrogen so attracts the electrons in the covalent bonds more strongly.

N2 Molecule

Optimisation

Calculation Method RB3LYP
Basis Set 6-31G(d,p)
Final Energy (au) -109.52412868
RMS Gradient (au) 0.00000060
Point Group D*H
Bond Length 1.11
Bond Angle 180
         Item               Value     Threshold  Converged?
 Maximum Force            0.000001     0.000450     YES
 RMS     Force            0.000001     0.000300     YES
 Maximum Displacement     0.000000     0.001800     YES
 RMS     Displacement     0.000000     0.001200     YES

Interactive Diagram

ammonia

Vibrations

There is only one vibration, because the molecule is linear and diatomic (3N-5).

H2 Molecule

Optimisation

Calculation Method RB3LYP
Basis Set 6-31G(d,p)
Final Energy (au) -1.17853935
RMS Gradient (au) 0.00003809
Point Group D*H
Bond Length 0.743
Bond Angle 180
         Item               Value     Threshold  Converged?
 Maximum Force            0.000066     0.000450     YES
 RMS     Force            0.000066     0.000300     YES
 Maximum Displacement     0.000087     0.001800     YES
 RMS     Displacement     0.000123     0.001200     YES

Interactive Diagram

ammonia

Vibrations

There is only one vibration, because the molecule is linear and diatomic (3N-5).

N2 + 3H2 → 2NH3

Reaction Energies (au)

E(NH3) -56.55776873
2*E(NH3) -113.1155375
E(N2) -109.52412868
E(H2) -1.17853935
3*E(H2) -3.53561805
ΔE=2*E(NH3)-[E(N2)+3*E(H2)] -0.05579073

Overall Reaction Energy (KJmol-1)

ΔE -146.48
Sum of energies of reactants Energy of product
-296838 -296966

The energy of ammonia is lower than the energies of the molecules from which it was formed, therefore it is more stable than the gaseous reactants.

ClF

Optimisation

Calculation Method RB3LYP
Basis Set 6-31G(d,p)
Final Energy (au) -559.94269578
RMS Gradient (au) 0.00014211
Point Group C*V
Bond Length 1.66434
Bond Angle 180
         Item               Value     Threshold  Converged?
 Maximum Force            0.000246     0.000450     YES
 RMS     Force            0.000246     0.000300     YES
 Maximum Displacement     0.000433     0.001800     YES
 RMS     Displacement     0.000613     0.001200     YES

Interactive Diagram

ammonia

Vibrations

There is only one vibration, because the molecule is linear and diatomic (3N-5). Here the vibration won't be even, because the chlorine atom is heavier, so will move a shorter distance than the fluorine atom from the point of equilibrium.

Charge

Chlorine 0.309
Flurorine -0.309

Fluorine is more electronegative than chlorine, so has a negative partial charge whilst chlorine's is positive.

Molecular Orbitals

MO7

This is the overlap of the bonding 3s AO from chlorine and the 2s from fluorine. It is occupied and is fairly deep in energy at -1.21864, and is the deepest out of the molecular orbitals, however not as deep as the non-bonding atomic orbitals.

MO8

This is the combination of the 3s AO from the chlorine and the 2s from the fluorine. It is an antibonding orbital and it is occupied. It is higher in energy at -0.83311.

MO9

This is the combination of the 3p from the chlorine and the 2p from the fluorine. This is an bonding orbital and it is occupied. It is again higher in energy at -0.52314.

MO10

This is the overlap of the 3p and 2p AOs. It is bonding and occupied. It is yet still higher in energy at -0.46713.

MO12

This is another combination of the 3p AO from chlorine and the 2p AO from fluorine, but this is antibonding and occupied. It is in the HOMO/LUMO region as the HOMO of the molecule at the energy -0.32855, meaning it is the highest of the occupied energy levels.

Cl2

Optimisation

Calculation Method RB3LYP
Basis Set 6-31G(d,p)
Final Energy (au) -920.34987886
RMS Gradient (au) 0.00002511
Point Group D*H
Bond Length 2.04
Bond Angle 180

Cl2 has a much lower energy than CLF, so is more stable.

         Item               Value     Threshold  Converged?
 Maximum Force            0.000043     0.000450     YES
 RMS     Force            0.000043     0.000300     YES
 Maximum Displacement     0.000121     0.001800     YES
 RMS     Displacement     0.000172     0.001200     YES

Interactive Diagram

chlorine

Vibrations

There is only one vibration, because the molecule is linear and diatomic (3N-5).

Charge

Chlorine 0

There is no difference in electronegativity between the two atoms, because they are the same element, hence why neither has a partial charge. This is different from ClF.