Computational Chemistry Lab

Introduction

Why do computational (inorganic) chemistry? Computational chemistry gives us insight into the structure and bonding of complexes. While bonding in organic systems is (for the most part) straight forward this is not the case for inorganic compounds and complexes!

Computational studies can differentiate between the energy of stable conformers, but more important is the location of transition states and activated complexes that may be difficult or impossible to characterise experimentally. Thermodynamic information is obtained from the energy of stable states, and from barrier heights (energy of a transition state) we can also obtain kinetic data.

An increasing number of properties can be usefully evaluated, for example IR and Raman spectra, NMR spectra, dipole moments. Analysis of the electron density gives us information on the bonding and local interactions between atoms.

For example an article in Chemistry World (05 June 2008) demonstrates one important use of calculations: designing better catalysts, Cheaper catalysts designed by computer: High-throughput calculations pluck out selective alloys to replace palladium

Instructions important

The first part of the lab (week 1) is lerning how to carry out calculations and is very detailed with step by step instructions, this is worth 30% of the marks. The second part of the lab (week 2) is a choice between several mini-projects where the instructions are more minimal and you are expected to apply the material and processes you have learned in the first section, the mini-project is worth 70% of the marks.

Guidelines for the time involved have been provided, if you find yourself deviating from this significantly it is very important that you contact a demonstrator or Dr. Hunt, early rather than late. You should have written up all of part one by the end of the first week.

REALLY important In the first part of the lab you are learning new things and it is easy to make a mistake, but not so easy to spot it. The computational lab is a bit different from the other labs in which we expect you to ASK FOR HELP, don't just keep repeating calculations. If you cannot see, or don't understand why your job has failed there is no point in repeating it. Learning happens through trying something, making mistakes and fixing it, this is not a failure, it is a learning process.

Getting help for your lab Getting help is like a doctors surgary, you goto the demonstrators at specified hours. You can find demonstrators and staff in the 2nd floor computer room. Your first port of call should be a demonstrator. Going into the computer room is the best way to get help! This is because all problems are better solved when they are explained face-to-face.

With the laptop you have the freedom to work on the lab in your own time, however if you run into problems you need to wait until the allocated demonstrator hours for help, take this into consideration when planning your work hours. Demonstrators and staff are available in person in very specific time slots. Students contacting staff demonstrators outside of these hours will be redirected to the appropriate times.

Hours demonstrators are available:
Demonstrators 1-3 Mon, Tue, Thur, Fri
Senior staff 2-3 Mon, Tue, Thur, Fri

To help you, there is a rapid feedback session on Friday 2-4. A demonstrator will check over the fist section with the aim of advising you of any missing or miss-understood components which you will then have a chance to correct. The rapid feedback is ONLY 2-4 Friday so be sure you are present in the computer room, and you have completed and written up all of the first weeks work. This will allow you to confidently move forward onto the second weeks project. The rapid feedback was very popular last year and we hope you will find it as useful this year. Manage your time up wisely!

If you need help on an administrative issue see the wiki for who you should e-mail.

Resources

  • lab demonstrators
  • your friends: ask them to see if they have solved your problem already, or brainstorm a solution
  • the Gaussian online manual
  • "Exploring Chemistry with Electronic Structure Methods", by JB Foresman and A. Frisch.
  • course content for MOs in Inorganic Chemistry


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