Following the procedure established for NH3 compute the optimised structures of N2 and H2. Linear molecules have D∞h symmetry. Don't forget to add the following in your wiki for each new molecule:
summary information
confirm the structure is converged via the "Item" section in the log file
JMol of structure
key structural information
snap shot of the display vibrations table confirming that there are no negative frequencies
table of vibrations and intensities
NBO charges
You may see an error like the one below, ignore it.
Now it is time to use a skill learned in your first computational lab! Use the web CCDC or ConQuest (which is on the softwarehub and which you have used already in IMM1) to find a mono-metallic TM complex that coordinates N2 OR H2, include the unique identifier for the structure and a link to the structure in your wiki, report the N-N or H-H bond distance you obtain and the equivalent distance in the structure you have found. Write a short paragraph explaining why the crystal structure and computational distances are the same or different, you should consider both computational and experimental reasons.
for example I found cis-tetrakis(Dimethylphenylphosphine)-bis(dinitrogen)-tungsten
structure DAYGEP and the two N-N distances are 1.119(4) and 1.126(4) Å
The Haber-Bosch process is the industrial means by which nitrogen gas and hydrogen gas are converted to ammonia. Ammonia is crucially important as a fertilizer. The reason we can support so many people in a limited area is that almost all farms in the western world use fertilizers extensively. More information can be found on the wikipedia
We can determine the energy for the reaction of N2 + 3H2 -> 2NH3. In your wiki complete the items below for energies in atomic units:
E(NH3)=
2*E(NH3)=
E(N2)=
E(H2)=
3*E(H2)=
ΔE=2*E(NH3)-[E(N2)+3*E(H2)]=
Important It is standard to report energy differences up to 1dp (one decimal place) in kJ/mol, thus 0.1 kJ/mol. Thus we need to know the energies in au to an accuracy that will allow us to report energy differences to the correct level. The important question is how much is 0.1 kJ/mol in au? 0.1 kJ/mol is 0.000038 au! So when reporting energies in au you must record them up to at least 5dp (recording up to 7dp is better and then drop the last two when reporting the data in a publication)
While total energies are normally reported in atomic units, which are hartree for energy, energy differences for chemical reactions are reported in kJ/mol. Thus convert your ΔE into kJ/mol, you could use a good web-based converter or just multiply this number by 2625.5.
In your wiki indicate the energy for converting hydrogen and nitrogen gas into ammonia gas in kJ/mol. Identify which is more stable the gaseous reactants or the ammonia product?
When you are ready close the molecule window move on to the next step
