Fluorobenzene

still of jmol image

Widgets will appear here

Fluorobenzene Quantum Calculations

All of the live displays on this page were created using the best optimized geometry. The best found geometry optimization was at the ab initio theory level of DZV.

The energy of the HOMO orbital is -0.3536 a.u.
The button below shows the HOMO orbital for fluorobenzene

The LUMO orbital of fluorobenzene is found at an energy of 0.1069 a.u.
Clicking the button below will show a live display of the LUMO orbital.

Clicking on the button below will display a live model of fluorobenzene with bond lengths.

The C-F bond has a length of 1.38 Å, this is higher than the literature value of 1.354 Å.¹ The percent error is 1.92%.

The two C-C bonds closest to the fluorine have a length of 1.38 Å, which is lower than the reference value of 1.392 Å.¹ The error percent of these bonds is 1.2%.

The remaining 4 C-C bonds have lengths of 1.4 Å. Comparing this to the literature value of 1.392 Å yields an error of 0.83%. ¹

The C-H bonds in the molecule have bond lengths of 1.07 Å. The error is 1.1% when compared to the literature value of 1.082 Å.¹

The button below shows bond angles of fluorobenzene.

All bond angles for this molecule are at or around the expected value of 120 degrees.

The DZV basis set was chosen as the best for this molecule because it is the largest of the tested basis sets. The DZV basis set, being larger, hopefully accounts for everything in this complex molecule.

The button below shows the partial atomic charges for fluorobenzene.

The button below shows the electrostatic potential for fluorobenzene.

The 8 main contributions to the energy vibrations are discussed and shown below.

The energy for the 1.36 vibration is 3446.6301 cm^-1. This is contributed to the symmetric C-H stretching.

The energy for the 1.32 vibration is 3405.6702 cm^-1. This shows assymmetrical C-H stretching.

The 1.30 vibration has an energy of 1791.2 cm^-1. There are two modes of this, and the button above is an example of one. This correlates to framework motions and stretching of the benzene ring.

The 1.29 vibration has an energy of 1652.37 cm^-1. This has two modes, and one example is shown above. This is contributed to the aromatic C-C stretching as well as stretching of the C-F bond.

The 1.27 vibration has an energy of 1472.25 cm^-1. This correlates to the stretching of the two C-C bonds parallel to the C-F bond as well as the wagging of C-H bonds.

Vibrational energy 1.25 correlates to the C-F stretching as well as C-C stretching. Two of the four hydrogens are wagging, which also adds to the energy. The energy is 1327.99 cm^-1.

C-F stretching and C-H bending correspond to vibration 1.24. The energy of this vibration is 1292.06 cm^-1.

C-H bending is responsible for vibration 1.17 and the energy is 1054.1799 cm^-1.

The IR spectrum for fluorobenzene below was found on the website for the spectral database system for organic compounds.²
Fluorobenzene IR Spectrum

Fluorobenzene IR Spectrum

The dipole moment for fluorobenzene was found to be 1.575356 Debye and when compared to the literature value of 1.66 Debye, has an error of 5.1%.¹ This was done using an AM1 basis set, which is a very small basis set in comparison to some of the other basis sets. The DZV basis set, which is the largest, actually had the worst dipole moment value out of all of them.

Below is a table of calculated excitation energies for UV-Vis spectroscopy of Fluorobenzene.

Basis Set	Excitation Energy (nm)	Oscillation Strength	Excited State
6-21G	186.02	0.017457	1
6-21G	138.38	1.108524	3
6-21G	136.98	1.150438	4
6-21G	124.79	0.009360	6
6-21G	114.75	0.001383	10
6-31G	189.64	0.012066	1
6-31G	182.20	0.001278	2
6-31G	141.08	1.119436	3
6-31G	139.75	1.194338	4
6-31G	129.69	0.003585	5
6-31G	125.33	0.009131	7
DZV	194.23	0.011203	1
DZV	187.01	0.002473	2
DZV	144.86	1.194734	3
DZV	143.94	1.271145	4
DZV	127.09	0.010794	5
DZV	124.90	0.020913	7
DZV	117.83	0.005455	9

Some excited state values were omitted from the table due to low oscillation strengths. The first excited states for each basis set each have a wavelength that falls within the first peak around 200nm, but the rest of the wavelengths fall outside the range of the experimental UV-Vis spectrum.

The following UV-Vis spectrum was obtained from the NIST.¹
UV-Vis Spectrum of Fluorbenzene

UV-Vis Spectrum of Fluorbenzene

References

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

Page skeleton and JavaScript generated by export to web function using Jmol 12.2.34 2012-08-09 20:37 on Feb 26, 2013.

Using directory /Users/student2/Desktop/Marissa Ryan/WEBSITE STUFF/Fluorobenzene
  adding JmolPopIn.js
  ...jmolApplet0
      ...adding HOMO__MO25_.png
      ...adding HOMO__MO25_.spt
  ...jmolApplet1
      ...adding LUMO__MO26_.png
      ...adding LUMO__MO26_.spt
  ...jmolApplet2
      ...adding Bond_Lengths.png
      ...adding Bond_Lengths.spt
  ...jmolApplet3
      ...adding Bond_Angles.png
      ...adding Bond_Angles.spt
  ...jmolApplet4
      ...adding DZV_Basis_Set.png
      ...adding DZV_Basis_Set.spt
  ...jmolApplet5
      ...adding Partial_Atomic_Charges.png
      ...adding Partial_Atomic_Charges.spt
  ...jmolApplet6
      ...adding Electrostatic_Potential.png
      ...adding Electrostatic_Potential.spt
  ...jmolApplet7
      ...adding Symmetric_Vibration_1_36.png
      ...adding Symmetric_Vibration_1_36.spt
  ...jmolApplet8
      ...adding Asymmetric_Vibration_1_32.png
      ...adding Asymmetric_Vibration_1_32.spt
  ...jmolApplet9
      ...adding Benzene_Ring_Vibration_1_30.png
      ...adding Benzene_Ring_Vibration_1_30.spt
  ...jmolApplet10
      ...adding Aromatic_C_C_Vibration_1_29.png
      ...adding Aromatic_C_C_Vibration_1_29.spt
  ...jmolApplet11
      ...adding Aromatic_C_C_Vibration_1_27.png
      ...adding Aromatic_C_C_Vibration_1_27.spt
  ...jmolApplet12
      ...adding C-F_Vibration_1_25.png
      ...adding C-F_Vibration_1_25.spt
  ...jmolApplet13
      ...adding C-F_Stretching___C-H_Bending_Vibrations_1_24.png
      ...adding C-F_Stretching___C-H_Bending_Vibrations_1_24.spt
  ...jmolApplet14
      ...adding C-H_Bending_Vibration_1_17.png
      ...adding C-H_Bending_Vibration_1_17.spt
  adding JmolSpin.js