Molecule: NH3;

Calculation method: RB3LYP;

Basis set: 6-31G(d,p);

Final energy E(RB3LYP): -56.44397188 a.u.;

RMS gradient: 0.05399560 a.u.;

Point group: C3V;

Optimised N-H bond distance: 1.018Å

;

Optimised H-N-H bond angle: 106°

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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

test molecule

The optimisation file is liked to here

File:Screenshot (2).png

vabration	wavenumber/cm-1	symmetry	intensity
1	1090	A1	145
2	1694	E	14
3	1694	E	14
4	3461	A1	1
5	3590	E	0
6	3590	E	0

how many modes do you expect from the 3N-6 rule? A: 6 modes.
which modes are degenerate (ie have the same energy)? A: 2 and 3, 5 and 6.
which modes are "bending" vibrations and which are "bond stretch" vibrations? A: 1, 2,3 are bending vibrations, 4, 5, 6 are bond stretch vibrations.
which mode is highly symmetric? A: 1,4 are highly symmetric.
one mode is known as the "umbrella" mode, which one is this? A: 1 is known as the "umbrella" mode.
how many bands would you expect to see in an experimental spectrum of gaseous ammonia? A: 4.

The charge on N-atom is -1.125, and the charge on H-atoms are 0.375. I would expect the charge on N-atom to be negative and the charge on H-atom to be positive, since nitrogen is more electronegative than hydrogen, the electrons in the bonds tend to be closer to the N-atom.

molecule	N2
Calculation Method	RB3LYP
Basis Set	6-31G(d,p)
Final energy E(RB3LYP)	-109.52359111 a.u.
RMS Gradient	0.02473091 a.u.
Point Group	D*H
Optimised bond length	1.09Å




         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

test molecule

NBO charges: 0

vibration	wavenumber/cm-1	symmetry	intensity
1	2457	SGG	0

molecule	H2
Calculation Method	RB3LYP
Basis Set	6-31G(d,p)
Final energy E(RB3LYP)	-1.15928020 a.u.
RMS Gradient	0.09719500 a.u.
Point Group	D*H
Optimised bond length	0.600Å




         Item               Value     Threshold  Converged?

 Maximum Force            0.000000     0.000450     YES

 RMS     Force            0.000000     0.000300     YES

 Maximum Displacement     0.000000     0.001800     YES

 RMS     Displacement     0.000001     0.001200     YES

test molecule

vibration	wavenumber/cm-1	symmetry	intensity
1	4466	SGG	0

The mono-metallic TM complex that coordinates H2 has a unique identifier REYMIS,

E(NH3)=-56.41397188 a.u. 2*E(NH3)=-112.82794376 a.u. E(N2)=-109.52359111 a.u. E(H2)=-1.15928020 a.u. 3*E(H2)=-3.4778406 a.u. ΔE=2*E(NH3)-[E(N2)+3*E(H2)]=0.17348795 a.u.= 0.17349 a.u.=455.5 kJ/mol

Gaseous reactants are more stable.

molecule     SH2
Calculation Method   RB3LYP
Basis Set            6-31G(d,p)
Final Energy E(RB3LYP)    -399.39162414  a.u.
RMS Gradient       0.00012068   a.u.
Point Group      C2V
Optimised S-H bond loength   1.35Å
Optimised H-S-H bonf angle   93°


         Item               Value     Threshold  Converged?
 Maximum Force            0.000175     0.000450     YES
 RMS     Force            0.000145     0.000300     YES
 Maximum Displacement     0.000386     0.001800     YES
 RMS     Displacement     0.000386     0.001200     YES

test molecule

The optimisation file is liked to here

vibration   wavenumber/cm-1   symmetry    intensity
1           1224                 A1          5
2            2692                A1         7
3           2712               B2           9

The charge on the S-atom is -0.164, the charges on the H-atoms are 0.082.

These MOs are contributed by 2p orbitals in the S-atom, are non-bonding orbitals, are high in energy. These 3 MOs are occupied by 2p electrons.

This MO is contributed by 3p orbitals in the S-atom, occupied by 3p electrons, and this is a non-bonding orbital, high in energy.

This MO is contributed by 3s orbitals in the S-atom overlapping s orbitals in the two H-atoms. This MO is bonding in the LUMO region. The S-H bonding is strong.

Marking

Note: All grades and comments are provisional and subject to change until your grades are officially returned via blackboard. Please do not contact anyone about anything to do with the marking of this lab until you have recieved your grade from blackboard.

Wiki structure and presentation 0/1

Is your wiki page clear and easy to follow, with consistent formatting? Do you effectively use tables, figures and subheadings to communicate your work?

Your wiki is a bit scrambled with no subheadings. The captions for your jmols are "test molecule" instead of ammonia etc. You should not use screenshots including your entire desktop in a lab report!

NH3 0.5/1

Have you completed the calculation and given a link to the file?

YES

Have you included summary and item tables in your wiki?

YES

Have you included a 3d jmol file or an image of the finished structure?

YES

Have you included the bond lengths and angles asked for?

YES

Have you included the “display vibrations” table?

YES

Have you added a table to your wiki listing the wavenumber and intensity of each vibration?

YES

Did you do the optional extra of adding images of the vibrations?

YES

Have you included answers to the questions about vibrations and charges in the lab script?

YES - good explanation of the charges and most of the vibration questions were answered correctly.

However due to the low intensity of vibrations 4, 5 and 6 you only see two peaks in the IR spectrum.

N2 and H2 0.5/0.5

Have you completed the calculations and included all relevant information? (summary, item table, structural information, jmol image, vibrations and charges)

YES

Crystal structure comparison 0/0.5

Have you included a link to a structure from the CCDC that includes a coordinated N2 or H2 molecule?

There is no link.

Have you compared your optimised bond distance to the crystal structure bond distance?

You have not compared the bond distances.

Haber-Bosch reaction energy calculation 0/1

Have you correctly calculated the energies asked for? ΔE=2*E(NH3)-[E(N2)+3*E(H2)]

No

Have you reported your answers to the correct number of decimal places?

YES

Do your energies have the correct +/- sign? No

Have you answered the question, Identify which is more stable the gaseous reactants or the ammonia product?

YES, but incorrectly - actually the product is more stable.

Your choice of small molecule 2.5/5

Have you completed the calculation and included all relevant information?

YES

Have you added information about MOs and charges on atoms?

YES - you have included some relevant information. You could have described the MOs in much more detail and explained the charges on the atoms in terms of electronegativity.

Independence 0/1

If you have finished everything else and have spare time in the lab you could: Check one of your results against the literature, or Do an extra calculation on another small molecule, or Do some deeper analysis on your results so far

No independent work.