View source for ZX2015Y101

== NH<sub>3</sub> Molecule ==

N-H bond distance = 1.01798 armstrong

H-N-H bond angle = 105.741 degree

=== Optimisation ===
Calculation Method : RB3LYP 

Basis Set : 6-31G(d,p)

Final energy E(RB3LYP) in atomic units (au)  : -56.55776873 

RMS gradient : 0.00000485

Point group : C3V

<jmol><jmolApplet>
    <title>Optimised NH<sub>3</sub> </title>
    <color>black</color>
    <size>200</size>
    <uploadedFileContents> NH3_OPTF_POP_ZX2015.LOG</uploadedFileContents>
</jmolApplet></jmol>



<pre>
         Item               Value     Threshold  Converged?
 Maximum Force            0.000004     0.000450     YES
 RMS     Force            0.000004     0.000300     YES
 Maximum Displacement     0.000072     0.001800     YES
 RMS     Displacement     0.000035     0.001200     YES

</pre>

=== Vibrations ===

[[ File:Display_vibration_zx2015.png|thumb|All modes of vibration of NH<sub>3</sub>|203x203px|right]]

Number of modes expected from the 3N-6 rule : 6 modes

Modes are degenerate (ie have the same energy) :  2&3 ; 5&6

Modes are "bending" vibrations : 1,2,3

Modes are "bond stretch" vibrations : 4,5,6

Mode is highly symmetric : 4

The "Umbrella" mode : 1

Number of bands expected to see in an experimental spectrum of gaseous ammonia : 2 bands
[[ File:NH3_Charge_distribution_zx2015.png|thumb|Charge distribution of NH<sub>3</sub>|203x203px]]

=== Charge distribution ===

Nitrogen in NH<sub>3</sub> has small negative charge of -1.125

Hydrogen in NH<sub>3</sub> has small positive charge of 0.375

Nitrogen atom is more electronegative than hydrogen atom. So the nitrogen atom pulls the pair of electrons towards itself. Therefore the nitrogen contains negative charge while the hydrogen is relatively positively charged. 

=== Reactivity ===
==== Molecule : N<sub>2</sub> ====

Calculation Method : RB3LYP

Basis Set : 6-31G(d,p)

Final energy E(RB3LYP) in atomic units (au)  :  -109.52412866

RMS gradient : 0.00012786

Point group : D∞h 

Vibration frequency : 2457.98

<jmol><jmolApplet>
    <title>Optimised NH<sub>3</sub> </title>
    <color>black</color>
    <size>200</size>
    <uploadedFileContents> N2_OPTF_POP_ZX2015.LOG</uploadedFileContents>
</jmolApplet></jmol>

<pre>
         Item               Value     Threshold  Converged?
 Maximum Force            0.000221     0.000450     YES
 RMS     Force            0.000221     0.000300     YES
 Maximum Displacement     0.000052     0.001800     YES
 RMS     Displacement     0.000098     0.001200     YES
</pre>

==== Molecule : H<sub>2</sub> ====

Calculation Method : RB3LYP

Basis Set : 6-31G(d,p)

Final energy E(RB3LYP) in atomic units (au)  :  -1.17853936

RMS gradient : 0.00002276

Point group : D∞h 

Vibration frequency : 4466.46

<jmol><jmolApplet>
    <title>Optimised NH<sub>3</sub> </title>
    <color>black</color>
    <size>200</size>
    <uploadedFileContents> H2_OPTF_POP_ZX2015.LOG</uploadedFileContents>
</jmolApplet></jmol>

<pre>
         Item               Value     Threshold  Converged?
 Maximum Force            0.000039     0.000450     YES
 RMS     Force            0.000039     0.000300     YES
 Maximum Displacement     0.000052     0.001800     YES
 RMS     Displacement     0.000073     0.001200     YES
</pre>

==== N2 + 3H2 -> 2NH3 ====

    * E(NH3)=  -56.55776873 au
    * 2*E(NH3)= -113.1155375 au
    * E(N2)=  -109.52412866 au
    * E(H2)= -1.17853936 au
    * 3*E(H2)= -3.53561808 au
    * ΔE=2*E(NH3)-[E(N2)+3*E(H2)]= -0.05579076 au
    * ΔE= -146.478651538 kj/mol
Therefore the product NH<sub>3</sub> is more stable.




== O<sub>2</sub> Molecule ==

[[File:O2_zx2015.png|thumb|O<sub>2</sub> molecule |203x203px]]
Dond distance = 1.21602 armstrong

Bond Angle = 180 degree
=== Optimisation ===

Calculation Method : RB3LYP

Basis Set : 6-31G(d,p)

Final energy E(RB3LYP) in atomic units (au)  :  -150.25742434

RMS gradient : 0.00007502

Point group : D∞h

Vibration frequency : 1642.74

<jmol><jmolApplet>
    <title>Optimised NH<sub>3</sub> </title>
    <color>black</color>
    <size>200</size>
    <uploadedFileContents> O2_OPTF_POP_ZX2015.LOG</uploadedFileContents>
</jmolApplet></jmol>


<pre>
         Item               Value     Threshold  Converged?
 Maximum Force            0.000130     0.000450     YES
 RMS     Force            0.000130     0.000300     YES
 Maximum Displacement     0.000080     0.001800     YES
 RMS     Displacement     0.000113     0.001200     YES
</pre>

=== Charge Distribution ===

[[File:O2_Charge_distribution_zx2015.png|thumb|Charge distribution of O<sub>2</sub> molecule |203x203px]]

Covalent Double Bond forms between two oxygen atoms. No charge on neither oxygen atom.




=== Molecular Orbitals ===
[[File:O2_MO1_zx2015.png|thumb|Lowest energy MO of O<sub>2</sub> molecule |203x203px|left]]







This MO is a bonding combination of the two 1s core AOs on each oxygen atom. It is filled by two electrons.

Because It is much deeper energy than MO formed by valence shell AOs, it does not involve in chemical bonding.








[[File:O2_MO3_zx2015.png|thumb|The 3rd MO of O<sub>2</sub> molecule |203x203px|left]]
[[File:O2_MO4_zx2015.png|thumb|The 4th MO of O<sub>2</sub> molecule |203x203px]]






The 3rd MO is a bonding combination of 2s valence AOs of each oxygen atom while the 4th MO is an anti-bonding combination of 2s valence AOs.

Both of these MOs are occupied. They are higher in energy, so they involve in chemical bonding.








[[File:O2_MO5_zx2015.png|thumb|The 5th MO of O<sub>2</sub> molecule |203x203px|left]]






The 5th MO is a bonding combination of 2p<sub>x</sub> valence AOs.MO is occupied.

Sigma 2p<sub>x</sub> bond is formed.

Its energy is higher than MOs formed by 2s AOs.








[[File:O2_MO6_zx2015.png|thumb|The 6th MO of O<sub>2</sub> molecule |203x203px|left]]







The 6th MO is a bonding combination of 2p<sub>y</sub> valence AOs. MO is occupied.

Pi 2p<sub>y</sub> bond is formed.

Its energy is even higher than MO gives sigma bond, so it is easier to be broken in a chemical reaction.