Styrene Calculations

Our best optimized geometry calculations were used to generate the displays you will see below. The level of ab initio used was 6-311G. The optimum geometry of the molecule was determined by trying different arangemetns of atoms until the energy of the system was at it lowest.

Click the button below to view an image of the optimized geometry for Styrene.

Styrene is an arromatic molecule with many different bond lengths and angles. By clicking on the two buttons below you will be able to view images of Styrene's bond lengths (angstroms) and bond angles.

To view experimental bond lengths for Styrene follow this link to the NIST website. The bolded numbers in the table on the website are the ones the calculated values can be compared to.

The difference between the calculated and experimental C-H bonds is about 1.2%, while the difference between the calculated and experimental C-C bonds ranges from about 0.1% to 0.7%.

Click on the button below to see and image of Styrene's HOMO, which stands for highest occupied molecular orbial. Molecular orbitals are defined as the wavefunctions for electrons in the molecule.

According to the MacMolPlt program the orbitals displayed are mostly P_z from the carbon atoms, and they don't seem to be contributing to bonding.

Styrene has 48 vibrational modes. By clicking on the buttons below you will be able to see images of the primary vibrational modes for Styrene.

This is the 47^th vibrational mode for Styrene. The vibrational frequency calculated was 3367.07 cm-1. This mostly due to C-H stretching at the end carbon with little stretching going on in the ring.

This is the 37^th vibrational mode for Styrene. The vibrational frequency calculated was 1666.34 cm-1. This is mostly due to C-H bending in the ring system with little bending at the end carbon.

This is the 21^st vibrational modes for Styrene. The vibrational frequency calculated was 1086.38 cm-1. This is mostly due to C-H bending at the end carbon and very little bending in the ring system.

This is the 16^th vibrational modes for Styrene. The vibrational frequency calculated was 790.26 cm-1. This is moslty due to C-H bending in the ring system and not very much at the end carbon.

According to the spectrum found on the NIST website all of these vibrations contribute to the major peaks that are present.

UV-vis transitions calculations were performed for the 3-21G and 6-31G levels of theory. Onely transiton with an oscillator strength of 0.2 or greater, from the ground state, were considered.

Exited State	3-21G Excitation Energy (eV)	3-21G Oscillator Strength	6-31G Excitation Energy (ev)	6-31G Oscillator Strength
1	6.07	0.410623	5.94	0.398984
3	7.75	0.816616	7.58	0.797982
4	8.25	0.897162	8.10	0.922298
6	9.34	0.248823	9.20	0.430590

To view a Styrene UV-vis spectra follow this link to the NIST website. Th most prominent peak is the one with the greatest oscillator stregth, which is the transition from the ground state to the 4^th exited state . The second most prominent peak is due to the transition to the 3^rd exited state.

The table below shows the calculated and experimental dipole moments for Styrene.

Level of Theory	Calculated Dipole Moment (debye)	Experimental Dipole Moment (debye)
3-21G	0.107543	0.140
6-31G	0.158199	0.140
6-311G	0.159057	0.140

All of our calculated results were compared to experimental data found on the NIST website:
http://cccbdb.nist.gov/

Based on template by A. Herráez as modified by J. Gutow

Page skeleton and JavaScript generated by export to web function using Jmol 11.6.6 2008-09-20 22:06 on Mar 17, 2009.

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