Building and optimizing propane-2-one (acetone) and animating its vibrations.

Start Oscail (Click means click the left mouse button)

On File select Ptest_\Moilin\scratch
Click to start Moilin if there are are any atoms on the screen click Purge on the menu.

Building Propan-2-one (acetone)

Click to go to build mode. Notice "Click Screen" on the status bar. Click the screen and the build dialog appears.

Click OK and methane appears since tetrahedral geometry and Atom Type C were selected.

Click one of the white H atoms and this time select planar geometry on the build dialog and click OK.

and the second carbon appears.

Click one of the H atoms on the planar carbon set the geometry to tetrahedral and click OK

Click the last H atom on the planar carbon and on the build dialog set the Atom Type to O (case does not matter), the geometry to monovalent and click OK.

The red oxygen appears.

Optimizing the structure and computing the IR spectrum

Click the right mouse button in the centre of the screen to go to display mode and click the button to bring up the Gamess menu.

To optimize using the AM1 method click NewInput and Run Gamess (AM1 optimize is the default)

When the calaculation is finished the message "Gamess finished structure updated" appears on the status bar.

To compute the IR spactrum again using the AM1 method click NewInput and select IR Spec. Hessian and Run Gamess.

On the Animate Vibration dialog select the C=O stretch. It is at 2061 cm-1 (It should be 1715 but higher levels of theory are required for a closer result) and OK.

The program will now animate the selected vibration.
Click cancel to end the animation action.

Making a movie of the vibration using Rasmov

You can make a movie of the vibrational mode for a web page or a powerpoint presentation from the movie files created by Moilin. If you exit Moilin by clicking the top right corner of the window (close button) a few times you will get the message Delete movie Files ?. Select NO.
 It is necessary to set the view position for Rasmov using Ortex. Click the button to start Ortex and use defaults. Set the view using the mouse to something like it was in Moilin.

Exit Ortex and click to start Rasmov. On the Rasmov dialog carefully select the following

Ellipsoid Type select Relative Atomic Radii and 20%
Image Properties select 384 x 320
Motion check MV*.INS
and OK
Rasmov will make the movie, put it into a web page and send the web page to the browser.
It should look like this

Any vibration at any calculation level may be animated in a similar manner.

Plotting the IR Spectrum

To obtain a realistic IR spectrum it is necessary to repeat the optimization using a higher level calculation. If you do this using 6-31G basis and dft the C=O stretch is now at 1816 cm^-1.
Select Properties / IR spectrum and on the scale factor dialog

enter 0.95 (1715/1816 = 0.95) The scaled IR spectrum will now be plotted.

The scaled spectrum is now displayed and the the C-H stretch vibrations can be used to test the result. C-H stretch on sp³ C should be just below 3000 and C-H stretch on sp² C should be just above 3000 cm^-1. It is easy to insert the spectrum into a WORD document etc. by pasting for the clipboard or by inserting the HPGL file. The scaled spectrum peak list is written to the GEO file.

Calculated and observed IR spectra for methyl acetate

The calculated spectrum (dft 6-31G) and

the observed spectrum

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