ChemWiki - User contributions [en]

Y2Mod:MG4417

2019-05-16T09:53:34Z

Mg4417:

=BH<sub>3</sub>=

Method/basis set: B3LYP/6-31G(d,p)

===Summary table===

[[File:Mg4417 BH3 summary.PNG|frameless]]

The LOG file is linked to [[Media:MG4417 BH3 FREQ.LOG| here]]

===Convergence and low frequency data===

<pre>
Item Value Threshold Converged?
Maximum Force 0.000014 0.000450 YES
RMS Force 0.000007 0.000300 YES
Maximum Displacement 0.000056 0.001800 YES
RMS Displacement 0.000028 0.001200 YES
Predicted change in Energy=-1.214268D-09

Low frequencies --- -8.2092 -1.7273 -0.0054 0.6025 6.1863 6.4229
Low frequencies --- 1162.9646 1213.1613 1213.1640
</pre>

<jmol><jmolApplet>
<title>optimised borane molecule</title>
<color>white</color>
<size>300</size>
<uploadedFileContents>MG4417 BH3 FREQ.LOG</uploadedFileContents>
<script>frame 1.8;spin on;zoom 200</script>
</jmolApplet></jmol>

===Spectrum and vibrational analysis===

[[File:Mg4417 BH3 spectrum.PNG|frameless|upright=1.7]]

{| class="wikitable" border="1"
! Mode !! Frequency !! Intensity !! Symmetry !! Description of vibration
|-
|1 || 1163 || 92.6 || A<sub>2</sub>" || symmetric bend, out of plane
|-
|2 || 1213 || 14.1 || E' || symmetric wag
|-
|3 || 1213 || 14.1 || E' || asymmetric wag
|-
|4 || 2582 || 0 || A<sub>1</sub>' || symmetric stretch, inactive
|-
|5 || 2716 || 126.3 || E' || asymmetric stretch
|-
|6 || 2716 || 126.3 || E' || asymmetric stretch
|}

===Why are there less than six peaks in the spectrum?===

Modes 2 and 3, as well as modes 5 and 6, are doubly degenerate so appear together on the spectrum. Mode 4 is IR inactive (since there is no change in dipole) so it does not appear at all on the IR spectrum.

===MO diagram===

[[file:mg4417_bh3_mo_diagram.png|frameless|upright=2]]

From [http://www.huntresearchgroup.org.uk/teaching/teaching_comp_lab_year2a/Tut_MO_diagram_BH3.pdf Hunt Research Group]

The LCAO MOs are similar to the real MOs with an obvious difference being the lack of overlap in the LCAO diagrams. The LCAO diagrams make it simple to identify involved orbitals and, with some knowledge of overlapping orbitals, we can easily approximate the electron distribution that would be seen in the real MOs so it is a useful tool. The LCAO orbitals are, of course, not sufficient for precise calculations.

=NH<sub>3</sub>=

Method/basis set: B3LYP/6-31G(d,p)

===Summary table===

[[File:Mg4417 nh3 summary.PNG|frameless]]

The LOG file is linked to [[Media:MG4417 NH3 FREQ.LOG| here]]

===Convergence and low frequency data===

<pre>
Item Value Threshold Converged?
Maximum Force 0.000005 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000012 0.001800 YES
RMS Displacement 0.000008 0.001200 YES
Predicted change in Energy=-9.075210D-11

Low frequencies --- -11.5223 -11.4866 -0.0029 0.0246 0.1415 25.6160
Low frequencies --- 1089.6618 1694.1735 1694.1738
</pre>

<jmol><jmolApplet>
<title>optimised ammonia molecule</title>
<color>white</color>
<size>300</size>
<uploadedFileContents>MG4417 NH3 FREQ.LOG</uploadedFileContents>
<script>frame 1.18;spin on;zoom 200</script>
</jmolApplet></jmol>

=NH<sub>3</sub>BH<sub>3</sub>=

Method/basis set: B3LYP/6-31G(d,p)

===Summary table===

[[File:Mg4417 NH3BH3 summary.PNG|frameless]]

The LOG file is linked to [[Media:MG4417 NH3BH3 FREQ.LOG| here]]

===Convergence and low frequency data===

<pre>
Item Value Threshold Converged?
Maximum Force 0.000121 0.000450 YES
RMS Force 0.000057 0.000300 YES
Maximum Displacement 0.000569 0.001800 YES
RMS Displacement 0.000318 0.001200 YES
Predicted change in Energy=-1.716563D-07

Low frequencies --- -0.0618 -0.0459 -0.0066 21.6264 21.6324 40.3000
Low frequencies --- 265.9346 632.2346 640.0641
</pre>

<jmol><jmolApplet>
<title>optimised NH3BH3 molecule</title>
<color>white</color>
<size>300</size>
<uploadedFileContents>MG4417 NH3BH3 FREQ.LOG</uploadedFileContents>
<script>frame 1.36;spin on;zoom 150</script>
</jmolApplet></jmol>

E(NH3)= -56.55776863

E(BH3)= -26.61532363

E(NH3BH3)= -83.22469013

ΔE=E(NH3BH3)-[E(NH3)+E(BH3)]

-83.22469013 - (-26.61532363 + -56.55776863) = -0.05159787 a.u.

1 hartree (a.u.) = 2625.5 kJ/mol

-0.05159787 a.u. = -135 kJ/mol (3 s.f.)

The normal bond enthalpy at 298 K of the B-N bond is 389 kJ/mol [[https://labs.chem.ucsb.edu/zakarian/armen/11---bonddissociationenergy.pdf ref]] so our calculated B-N dative bond is relatively weak.

=NI<sub>3</sub>=

Method/basis set: B3LYP/GEN (N: 6-31G(d,p); I: LanL2DZ)

===Summary table===

[[File:Mg4417 ni3 summary.PNG|frameless]]

The LOG file is linked to [[Media:MG4417 NI3 FREQ.LOG| here]]

===Convergence and low frequency data===

<pre>
Item Value Threshold Converged?
Maximum Force 0.000067 0.000450 YES
RMS Force 0.000044 0.000300 YES
Maximum Displacement 0.000486 0.001800 YES
RMS Displacement 0.000363 0.001200 YES
Predicted change in Energy=-6.369422D-08

Low frequencies --- -12.7375 -12.7314 -6.2898 -0.0039 0.0188 0.0633
Low frequencies --- 101.0325 101.0332 147.4122
</pre>

<jmol><jmolApplet>
<title>optimised NI3 molecule</title>
<color>white</color>
<size>300</size>
<uploadedFileContents>MG4417 NI3 FREQ.LOG</uploadedFileContents>
<script>frame 1.20;spin on;zoom 200</script>
</jmolApplet></jmol>

The optimised B-I bond distance was found to be 2.184 Å.

=Project: Main Group Halides- Al<sub>2</sub>Cl<sub>4</sub>Br<sub>2</sub>=

Isomers of Al<sub>2</sub>Cl<sub>4</sub>Br<sub>2</sub> with symmetry point groups.

[[File:MG4417 ISOMERS.PNG|frameless|upright=2]]

==Energy of two isomers==

Energy calculations were carried out twice. First with a pseudo-potential on all atoms, this was done because it would make for the most reliable comparison between isomers. It would be unreliable to attribute changes between isomers to only changing position and not to the pseudo-potential. After difficulties in attaining convergence with these calculations, the pseudo-potential was only applied on the heaviest atom, Br. Both tests are included in this work, however only the second can be considered reliable due to problems with convergence in the first.

==Pseudo-potential on all atoms==
===Bridging Br===

Method/basis set: B3LYP/LanL2DZ

'''Summary table'''

[[File:MG4417 BRIDGING BR PS SUMMARY.PNG|frameless]]

The LOG file is linked to [[Media:MG4417 BRIDGING BR PS.LOG| here]]

'''Convergence and low frequency data'''

<pre>
Item Value Threshold Converged?
Maximum Force 0.000035 0.000450 YES
RMS Force 0.000014 0.000300 YES
Maximum Displacement 0.000585 0.001800 YES
RMS Displacement 0.000195 0.001200 YES
Predicted change in Energy=-5.296151D-08

Low frequencies --- -3.1172 -1.5998 0.0000 0.0000 0.0000 3.0050
Low frequencies --- 16.6606 52.3978 72.9198
</pre>

<jmol><jmolApplet>
<title>optimised molecule</title>
<color>white</color>
<size>300</size>
<uploadedFileContents>MG4417 BRIDGING BR PS.LOG</uploadedFileContents>
<script>frame 1.38;spin on;zoom 150</script>
</jmolApplet></jmol>

===Trans terminal Br===

Method/basis set: B3LYP/LanL2DZ

'''Summary table'''

[[File:MG4417 TRANS BR PS SUMMARY.PNG|frameless]]

The LOG file is linked to [[Media:MG4417 TRANS BR PS.LOG| here]]

'''Convergence and low frequency data'''

<pre>
Item Value Threshold Converged?
Maximum Force 0.000076 0.000450 YES
RMS Force 0.000027 0.000300 YES
Maximum Displacement 0.001683 0.001800 YES
RMS Displacement 0.000526 0.001200 YES
Predicted change in Energy=-1.279182D-07

Low frequencies --- -2.6678 -0.0001 0.0000 0.0001 3.1983 3.3077
Low frequencies --- 18.0970 40.4821 64.5629
</pre>

<jmol><jmolApplet>
<title>optimised molecule</title>
<color>white</color>
<size>300</size>
<uploadedFileContents>MG4417 TRANS BR PS.LOG</uploadedFileContents>
<script>frame 1.34;spin on;zoom 150</script>
</jmolApplet></jmol>

===Monomer- AlCl<sub>2</sub>Br===

Method/basis set: B3LYP/LanL2DZ

'''Summary table'''

[[File:MG4417 MONO BR PS SUMMARY.PNG|frameless]]

The LOG file is linked to [[Media:MG4417 MONO BR PS.LOG| here]]

'''Convergence and low frequency data'''

<pre>
Item Value Threshold Converged?
Maximum Force 0.000146 0.000450 YES
RMS Force 0.000078 0.000300 YES
Maximum Displacement 0.001928 0.001800 NO
RMS Displacement 0.001635 0.001200 NO
Predicted change in Energy=-2.520022D-07

Low frequencies --- 0.0000 0.0000 0.0000 3.6917 4.9979 6.2169
Low frequencies --- 108.1004 119.9123 168.6209
</pre>

This test may have not converged because using a pseudo-potential on all atoms in this case is not appropriate. Furthermore, it could have been that the LanL2DZ basis set was not accurate enough for this particular calculation.

<jmol><jmolApplet>
<title>optimised molecule</title>
<color>white</color>
<size>300</size>
<uploadedFileContents>MG4417 MONO BR PS.LOG</uploadedFileContents>
<script>frame 1.20;spin on;zoom 150</script>
</jmolApplet></jmol>

===Results===

E(Br trans)= -90.47287952 a.u.

E(Br bridging)= -90.46237262 a.u.

E(Br trans) - E(Br bridging)= -0.0105069 a.u. = -27.6 kJ/mol.

Isomer with Br trans is more stable, discussion in following section.

Dissociation energy of this isomer:

2(E(monomer))-E(trans)

2(-45.21900101)-(-90.47287952)= 0.0348775 a.u. = 91.6 kJ/mol.

Positive energy tells us that this isomer is lower in energy than the dissociation products.

==Pseudo-potential on Br==
===Bridging Br===

Method/basis set: B3LYP/GEN (Al, Cl: 6-31G(d,p); Br: LanL2DZ)

'''Summary table'''

[[File:MG4417 BRIDGING BR SUMMARY.PNG|frameless]]

The LOG file is linked to [[Media:MG4417 BRIDGING BR.LOG| here]]

'''Convergence and low frequency data'''

<pre>
Item Value Threshold Converged?
Maximum Force 0.000068 0.000450 YES
RMS Force 0.000028 0.000300 YES
Maximum Displacement 0.001356 0.001800 YES
RMS Displacement 0.000596 0.001200 YES
Predicted change in Energy=-1.340348D-07

Low frequencies --- -5.4042 -5.0662 -3.4974 -0.0040 -0.0036 -0.0027
Low frequencies --- 14.8547 63.2537 86.0200
</pre>

<jmol><jmolApplet>
<title>optimised molecule</title>
<color>white</color>
<size>300</size>
<uploadedFileContents>MG4417 BRIDGING BR.LOG</uploadedFileContents>
<script>frame 1.36;spin on;zoom 150</script>
</jmolApplet></jmol>

===Trans terminal Br===

Method/basis set: B3LYP/GEN (Al, Cl: 6-31G(d,p); Br: LanL2DZ)

'''Summary table'''

[[File:MG4417 TRANS BR SUMMARY.PNG|frameless]]

The LOG file is linked to [[Media:MG4417 TRANS BR.LOG| here]]

'''Convergence and low frequency data'''

<pre>
Item Value Threshold Converged?
Maximum Force 0.000025 0.000450 YES
RMS Force 0.000011 0.000300 YES
Maximum Displacement 0.000503 0.001800 YES
RMS Displacement 0.000212 0.001200 YES
Predicted change in Energy=-2.217341D-08

Low frequencies --- -4.2264 -2.1529 -0.0020 0.0022 0.0031 1.1140
Low frequencies --- 17.7223 48.9616 72.9504
</pre>

<jmol><jmolApplet>
<title>optimised molecule</title>
<color>white</color>
<size>300</size>
<uploadedFileContents>MG4417 TRANS BR.LOG</uploadedFileContents>
<script>frame 1.38;spin on;zoom 150</script>
</jmolApplet></jmol>

===Monomer- AlCl<sub>2</sub>Br===

Method/basis set: B3LYP/GEN (Al, Cl: 6-31G(d,p); Br: LanL2DZ)

'''Summary table'''

[[File:MG4417 MONO BR SUMMARY.PNG|frameless]]

The LOG file is linked to [[Media:MG4417 MONO BR.LOG| here]]

'''Convergence and low frequency data'''

<pre>
Item Value Threshold Converged?
Maximum Force 0.000054 0.000450 YES
RMS Force 0.000022 0.000300 YES
Maximum Displacement 0.000277 0.001800 YES
RMS Displacement 0.000129 0.001200 YES
Predicted change in Energy=-1.128145D-08

Low frequencies --- -3.1104 -0.0027 0.0012 0.0035 1.9802 2.3808
Low frequencies --- 120.5065 133.8377 185.7407
</pre>

<jmol><jmolApplet>
<title>optimised molecule</title>
<color>white</color>
<size>300</size>
<uploadedFileContents>MG4417 MONO BR.LOG</uploadedFileContents>
<script>frame 1.22;spin on;zoom 150</script>
</jmolApplet></jmol>

===Results===

E(Br trans)= -2352.41628813 a.u.

E(Br bridging)= -2352.40630785 a.u.

E(Br trans) - E(Br bridging)= -0.00998028 a.u. = -26.2 kJ/mol.

Isomer with Br trans is more stable. Intuitively, this makes sense since the bromide substituents are large and the trans arrangement maximises the distance between the two Br atoms and minimises repulsion, lowering the energy of the molecule. An arrangement with bridging Cl atoms may be favourable also, perhaps because the chlorine atom is compact and so has better overlap with the Al (similar in radius to Cl) orbitals involved in the central bonding structure. A more stable bond between the Al and the bridging atom is, of course, an important contribution the overall stability.

Dissociation energy of this isomer:

2(E(monomer))-E(trans)

2(-1176.19013696)-(-2352.41628813)= 0.03601420999 a.u. = 94.6 kJ/mol.

Positive energy tells us that this isomer is lower in energy than the dissociation products. The dimer completes an octet of electrons around the aluminium centres so this is expected to be more stable. Hyperconjugation of the p orbitals on Al (empty) and the filled p orbitals of Br and Cl does occur in the monomer so the energy is not so high that it is completely unfavourable but dimerisation provides further stabilisation by the donation of lone pairs from the bridging atoms into the aluminium centres and the subsequent formation of new molecular orbitals resulting in stability.

==Molecular orbitals of the Br trans isomer==

MO 17

[[File:Mg4417 17 annotated.png|frameless|upright=2]]

MO 21

[[File:Mg4417 21 annotated.png|frameless|upright=2]]

MO 23

[[File:Mg4417 23 annotated.png|frameless|upright=2]]

File:Mg4417 23 annotated.png

2019-05-16T09:49:40Z

Mg4417:

File:Mg4417 21 annotated.png

2019-05-16T09:49:10Z

Mg4417:

File:Mg4417 17 annotated.png

2019-05-16T09:48:28Z

Mg4417:

2019-05-15T15:58:47Z

Mg4417: /* Pseudo-potential on Br */

=BH<sub>3</sub>=

Method/basis set: B3LYP/6-31G(d,p)

===Summary table===

[[File:Mg4417 BH3 summary.PNG|frameless]]

The LOG file is linked to [[Media:MG4417 BH3 FREQ.LOG| here]]

===Convergence and low frequency data===

<pre>
Item Value Threshold Converged?
Maximum Force 0.000014 0.000450 YES
RMS Force 0.000007 0.000300 YES
Maximum Displacement 0.000056 0.001800 YES
RMS Displacement 0.000028 0.001200 YES
Predicted change in Energy=-1.214268D-09

Low frequencies --- -8.2092 -1.7273 -0.0054 0.6025 6.1863 6.4229
Low frequencies --- 1162.9646 1213.1613 1213.1640
</pre>

<jmol><jmolApplet>
<title>optimised borane molecule</title>
<color>white</color>
<size>300</size>
<uploadedFileContents>MG4417 BH3 FREQ.LOG</uploadedFileContents>
<script>frame 1.8;spin on;zoom 200</script>
</jmolApplet></jmol>

===Spectrum and vibrational analysis===

[[File:Mg4417 BH3 spectrum.PNG|frameless|upright=1.7]]

{| class="wikitable" border="1"
! Mode !! Frequency !! Intensity !! Symmetry !! Description of vibration
|-
|1 || 1163 || 92.6 || A<sub>2</sub>" || symmetric bend, out of plane
|-
|2 || 1213 || 14.1 || E' || symmetric wag
|-
|3 || 1213 || 14.1 || E' || asymmetric wag
|-
|4 || 2582 || 0 || A<sub>1</sub>' || symmetric stretch, inactive
|-
|5 || 2716 || 126.3 || E' || asymmetric stretch
|-
|6 || 2716 || 126.3 || E' || asymmetric stretch
|}

===Why are there less than six peaks in the spectrum?===

Modes 2 and 3, as well as modes 5 and 6, are doubly degenerate so appear together on the spectrum. Mode 4 is IR inactive (since there is no change in dipole) so it does not appear at all on the IR spectrum.

===MO diagram===

[[file:mg4417_bh3_mo_diagram.png|frameless|upright=2]]

From [http://www.huntresearchgroup.org.uk/teaching/teaching_comp_lab_year2a/Tut_MO_diagram_BH3.pdf Hunt Research Group]

The LCAO MOs are similar to the real MOs with an obvious difference being the lack of overlap in the LCAO diagrams. The LCAO diagrams make it simple to identify involved orbitals and, with some knowledge of overlapping orbitals, we can easily approximate the electron distribution that would be seen in the real MOs so it is a useful tool. The LCAO orbitals are, of course, not sufficient for precise calculations.

=NH<sub>3</sub>=

Method/basis set: B3LYP/6-31G(d,p)

===Summary table===

[[File:Mg4417 nh3 summary.PNG|frameless]]

The LOG file is linked to [[Media:MG4417 NH3 FREQ.LOG| here]]

===Convergence and low frequency data===

<pre>
Item Value Threshold Converged?
Maximum Force 0.000005 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000012 0.001800 YES
RMS Displacement 0.000008 0.001200 YES
Predicted change in Energy=-9.075210D-11

Low frequencies --- -11.5223 -11.4866 -0.0029 0.0246 0.1415 25.6160
Low frequencies --- 1089.6618 1694.1735 1694.1738
</pre>

<jmol><jmolApplet>
<title>optimised ammonia molecule</title>
<color>white</color>
<size>300</size>
<uploadedFileContents>MG4417 NH3 FREQ.LOG</uploadedFileContents>
<script>frame 1.18;spin on;zoom 200</script>
</jmolApplet></jmol>

=NH<sub>3</sub>BH<sub>3</sub>=

Method/basis set: B3LYP/6-31G(d,p)

===Summary table===

[[File:Mg4417 NH3BH3 summary.PNG|frameless]]

The LOG file is linked to [[Media:MG4417 NH3BH3 FREQ.LOG| here]]

===Convergence and low frequency data===

<pre>
Item Value Threshold Converged?
Maximum Force 0.000121 0.000450 YES
RMS Force 0.000057 0.000300 YES
Maximum Displacement 0.000569 0.001800 YES
RMS Displacement 0.000318 0.001200 YES
Predicted change in Energy=-1.716563D-07

Low frequencies --- -0.0618 -0.0459 -0.0066 21.6264 21.6324 40.3000
Low frequencies --- 265.9346 632.2346 640.0641
</pre>

<jmol><jmolApplet>
<title>optimised NH3BH3 molecule</title>
<color>white</color>
<size>300</size>
<uploadedFileContents>MG4417 NH3BH3 FREQ.LOG</uploadedFileContents>
<script>frame 1.36;spin on;zoom 150</script>
</jmolApplet></jmol>

E(NH3)= -56.55776863

E(BH3)= -26.61532363

E(NH3BH3)= -83.22469013

ΔE=E(NH3BH3)-[E(NH3)+E(BH3)]

-83.22469013 - (-26.61532363 + -56.55776863) = -0.05159787 a.u.

1 hartree (a.u.) = 2625.5 kJ/mol

-0.05159787 a.u. = -135 kJ/mol (3 s.f.)

The normal bond enthalpy at 298 K of the B-N bond is 389 kJ/mol [[https://labs.chem.ucsb.edu/zakarian/armen/11---bonddissociationenergy.pdf ref]] so our calculated B-N dative bond is relatively weak.

=NI<sub>3</sub>=

Method/basis set: B3LYP/GEN (N: 6-31G(d,p); I: LanL2DZ)

===Summary table===

[[File:Mg4417 ni3 summary.PNG|frameless]]

The LOG file is linked to [[Media:MG4417 NI3 FREQ.LOG| here]]

===Convergence and low frequency data===

<pre>
Item Value Threshold Converged?
Maximum Force 0.000067 0.000450 YES
RMS Force 0.000044 0.000300 YES
Maximum Displacement 0.000486 0.001800 YES
RMS Displacement 0.000363 0.001200 YES
Predicted change in Energy=-6.369422D-08

Low frequencies --- -12.7375 -12.7314 -6.2898 -0.0039 0.0188 0.0633
Low frequencies --- 101.0325 101.0332 147.4122
</pre>

<jmol><jmolApplet>
<title>optimised NI3 molecule</title>
<color>white</color>
<size>300</size>
<uploadedFileContents>MG4417 NI3 FREQ.LOG</uploadedFileContents>
<script>frame 1.20;spin on;zoom 200</script>
</jmolApplet></jmol>

The optimised B-I bond distance was found to be 2.184 Å.

=Project: Main Group Halides- Al<sub>2</sub>Cl<sub>4</sub>Br<sub>2</sub>=

Isomers of Al<sub>2</sub>Cl<sub>4</sub>Br<sub>2</sub> with symmetry point groups.

[[File:MG4417 ISOMERS.PNG|frameless|upright=2]]

==Energy of two isomers==

Energy calculations were carried out twice. First with a pseudo-potential on all atoms, this was done because it would make for the most reliable comparison between isomers. It would be unreliable to attribute changes between isomers to only changing position and not to the pseudo-potential. After difficulties in attaining convergence with these calculations, the pseudo-potential was only applied on the heaviest atom, Br. Both tests are included in this work, however only the second can be considered reliable due to problems with convergence in the first.

==Pseudo-potential on all atoms==
===Bridging Br===

Method/basis set: B3LYP/LanL2DZ

'''Summary table'''

[[File:MG4417 BRIDGING BR PS SUMMARY.PNG|frameless]]

The LOG file is linked to [[Media:MG4417 BRIDGING BR PS.LOG| here]]

'''Convergence and low frequency data'''

<pre>
Item Value Threshold Converged?
Maximum Force 0.000035 0.000450 YES
RMS Force 0.000014 0.000300 YES
Maximum Displacement 0.000585 0.001800 YES
RMS Displacement 0.000195 0.001200 YES
Predicted change in Energy=-5.296151D-08

Low frequencies --- -3.1172 -1.5998 0.0000 0.0000 0.0000 3.0050
Low frequencies --- 16.6606 52.3978 72.9198
</pre>

<jmol><jmolApplet>
<title>optimised molecule</title>
<color>white</color>
<size>300</size>
<uploadedFileContents>MG4417 BRIDGING BR PS.LOG</uploadedFileContents>
<script>frame 1.38;spin on;zoom 150</script>
</jmolApplet></jmol>

===Trans terminal Br===

Method/basis set: B3LYP/LanL2DZ

'''Summary table'''

[[File:MG4417 TRANS BR PS SUMMARY.PNG|frameless]]

The LOG file is linked to [[Media:MG4417 TRANS BR PS.LOG| here]]

'''Convergence and low frequency data'''

<pre>
Item Value Threshold Converged?
Maximum Force 0.000076 0.000450 YES
RMS Force 0.000027 0.000300 YES
Maximum Displacement 0.001683 0.001800 YES
RMS Displacement 0.000526 0.001200 YES
Predicted change in Energy=-1.279182D-07

Low frequencies --- -2.6678 -0.0001 0.0000 0.0001 3.1983 3.3077
Low frequencies --- 18.0970 40.4821 64.5629
</pre>

<jmol><jmolApplet>
<title>optimised molecule</title>
<color>white</color>
<size>300</size>
<uploadedFileContents>MG4417 TRANS BR PS.LOG</uploadedFileContents>
<script>frame 1.34;spin on;zoom 150</script>
</jmolApplet></jmol>

===Monomer- AlCl<sub>2</sub>Br===

Method/basis set: B3LYP/LanL2DZ

'''Summary table'''

[[File:MG4417 MONO BR PS SUMMARY.PNG|frameless]]

The LOG file is linked to [[Media:MG4417 MONO BR PS.LOG| here]]

'''Convergence and low frequency data'''

<pre>
Item Value Threshold Converged?
Maximum Force 0.000146 0.000450 YES
RMS Force 0.000078 0.000300 YES
Maximum Displacement 0.001928 0.001800 NO
RMS Displacement 0.001635 0.001200 NO
Predicted change in Energy=-2.520022D-07

Low frequencies --- 0.0000 0.0000 0.0000 3.6917 4.9979 6.2169
Low frequencies --- 108.1004 119.9123 168.6209
</pre>

<jmol><jmolApplet>
<title>optimised molecule</title>
<color>white</color>
<size>300</size>
<uploadedFileContents>MG4417 MONO BR PS.LOG</uploadedFileContents>
<script>frame 1.20;spin on;zoom 150</script>
</jmolApplet></jmol>

'''Results'''

E(Br trans)= -90.47287952 a.u.

E(Br bridging)= -90.46237262 a.u.

E(Br trans) - E(Br bridging)= -0.0105069 a.u. = -27.6 kJ/mol.

Isomer with Br trans is more stable, discussion in following section.

Dissociation energy of this isomer:

2(E(monomer))-E(trans)

2(-45.21900101)-(-90.47287952)= 0.0348775 a.u. = 91.6 kJ/mol.

Positive energy tells us that this isomer is more stable than the two dissociation products.

==Pseudo-potential on Br==
===Bridging Br===

Method/basis set: B3LYP/GEN (Al, Cl: 6-31G(d,p); Br: LanL2DZ)

'''Summary table'''

[[File:MG4417 BRIDGING BR PS SUMMARY.PNG|frameless]]

The LOG file is linked to [[Media:MG4417 BRIDGING BR PS.LOG| here]]

'''Convergence and low frequency data'''

<pre>
Item Value Threshold Converged?
Maximum Force 0.000035 0.000450 YES
RMS Force 0.000014 0.000300 YES
Maximum Displacement 0.000585 0.001800 YES
RMS Displacement 0.000195 0.001200 YES
Predicted change in Energy=-5.296151D-08

Low frequencies --- -3.1172 -1.5998 0.0000 0.0000 0.0000 3.0050
Low frequencies --- 16.6606 52.3978 72.9198
</pre>

<jmol><jmolApplet>
<title>optimised molecule</title>
<color>white</color>
<size>300</size>
<uploadedFileContents>MG4417 BRIDGING BR PS.LOG</uploadedFileContents>
<script>frame 1.38;spin on;zoom 150</script>
</jmolApplet></jmol>

===Trans terminal Br===

Method/basis set: B3LYP/GEN (Al, Cl: 6-31G(d,p); Br: LanL2DZ)

'''Summary table'''

[[File:MG4417 TRANS BR PS SUMMARY.PNG|frameless]]

The LOG file is linked to [[Media:MG4417 TRANS BR PS.LOG| here]]

'''Convergence and low frequency data'''

<pre>
Item Value Threshold Converged?
Maximum Force 0.000076 0.000450 YES
RMS Force 0.000027 0.000300 YES
Maximum Displacement 0.001683 0.001800 YES
RMS Displacement 0.000526 0.001200 YES
Predicted change in Energy=-1.279182D-07

Low frequencies --- -2.6678 -0.0001 0.0000 0.0001 3.1983 3.3077
Low frequencies --- 18.0970 40.4821 64.5629
</pre>

<jmol><jmolApplet>
<title>optimised molecule</title>
<color>white</color>
<size>300</size>
<uploadedFileContents>MG4417 TRANS BR PS.LOG</uploadedFileContents>
<script>frame 1.34;spin on;zoom 150</script>
</jmolApplet></jmol>

===Monomer- AlCl<sub>2</sub>Br===

Method/basis set: B3LYP/GEN (Al, Cl: 6-31G(d,p); Br: LanL2DZ)

'''Summary table'''

[[File:MG4417 MONO BR PS SUMMARY.PNG|frameless]]

The LOG file is linked to [[Media:MG4417 MONO BR PS.LOG| here]]

'''Convergence and low frequency data'''

<pre>
Item Value Threshold Converged?
Maximum Force 0.000146 0.000450 YES
RMS Force 0.000078 0.000300 YES
Maximum Displacement 0.001928 0.001800 NO
RMS Displacement 0.001635 0.001200 NO
Predicted change in Energy=-2.520022D-07

Low frequencies --- 0.0000 0.0000 0.0000 3.6917 4.9979 6.2169
Low frequencies --- 108.1004 119.9123 168.6209
</pre>

<jmol><jmolApplet>
<title>optimised molecule</title>
<color>white</color>
<size>300</size>
<uploadedFileContents>MG4417 MONO BR PS.LOG</uploadedFileContents>
<script>frame 1.20;spin on;zoom 150</script>
</jmolApplet></jmol>

'''Results'''

E(Br trans)= -90.47287952 a.u.

E(Br bridging)= -90.46237262 a.u.

E(Br trans) - E(Br bridging)= -0.0105069 a.u. = -27.6 kJ/mol.

Isomer with Br trans is more stable, discussion in following section.

Dissociation energy of this isomer:

2(E(monomer))-E(trans)

2(-45.21900101)-(-90.47287952)= 0.0348775 a.u. = 91.6 kJ/mol.

Positive energy tells us that this isomer is more stable than the two dissociation products.

Y2Mod:MG4417

2019-05-14T12:44:12Z

Mg4417: /* MO diagram */