Difference between revisions of "Hayalex1"

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<uploadedFileContents>AH_ME3NHCL_OPTF.LOG</uploadedFileContents>
 
<uploadedFileContents>AH_ME3NHCL_OPTF.LOG</uploadedFileContents>
 
</jmolApplet></jmol>
 
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===Rigid scan===
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A rigid scan was performed, measuring the potential energy curve produced by increasing the N-H bond length from 0.8&Acirc; to 2.1&Acirc; in 0.1&Acirc; steps.

Revision as of 05:56, 20 May 2026

lab marking

You have a good working wiki. It would be good if you report values of wavenumber in your answers. Overall a very good attempt. If you have any specific questions, do email Prof. Hunt

NH3

Calculation Data

Optimisation of NH3 was performed using the following parameters:

Log file AH_opf_pop.log
Molecule NH3
Method RB3LYP
Basis set 6-31G(d,p)
Final energy -56.55777 au
RMS gradient 0.000000
Point group C3V

Log file

Media:AH_NH3_OPF_POP.LOG

Convergence data

The following data was collected from the log file, confirming convergence.

Item table

         Item               Value     Threshold  Converged?
 Maximum Force            0.000000     0.000015     YES
 RMS     Force            0.000000     0.000010     YES
 Maximum Displacement     0.000003     0.000060     YES
 RMS     Displacement     0.000001     0.000040     YES

Low frequencies

 Low frequencies ---   -5.6864   -3.6131   -3.6124    0.0017    0.0048    0.0162
 Low frequencies --- 1089.3674 1693.9284 1693.9284

Optimised molecule

Molecule parameters

  • r(N-H): 1.02Â
  • θ(H-N-H): 106°

Molecular structure

NH3 top-down view

AH nh3 opf.PNG

NH₃ 3D view


Vibrational analysis and IR spectrum

Mode 1 2 3 4 5 6
Wavenumber (cm-1) 1089 1694 1694 3461 3590 3590
Symmetry A1 E E A1 E E
Intensity 145 14 14 1 0 0

AH NH3 OPF POP IR.PNG

Charge distribution

Atom N H
Charge (e) -1.13 +0.38

AH NH3 OPF CDISTCONFIG.PNG

AH NH3 OPF CHARGEDIST.PNG


cis-N2F2 (Project molecule)

Calculation Data

Optimisation of N2F2 was performed using the following parameters:

Log file AH_N2F2_OPTF_POP.LOG
Molecule N2F2
Method RB3LYP
Basis set 6-31G(d,p)
Final energy -309.01241 au
RMS gradient 0.000000
Point group C2V

Log file

Media:AH_N2F2_OPTF_POP.LOG

Convergence data

The following data was collected from the log file, confirming convergence.

Item table

         Item               Value     Threshold  Converged?
 Maximum Force            0.000001     0.000015     YES
 RMS     Force            0.000000     0.000010     YES
 Maximum Displacement     0.000001     0.000060     YES
 RMS     Displacement     0.000001     0.000040     YES

Low frequencies

 Low frequencies ---    0.0014    0.0022    0.0022    3.2225    4.3532    5.1001
 Low frequencies ---  347.8772  561.2472  771.6105

Optimised molecule

Molecule parameters

  • r(N-F): 1.39Â
  • r(N=N): 1.22Â
  • θ(F-N=N): 114°
  • θ(F-N=N-F): 0°

Molecular structure

N2F2 2D view

AH N2F2 OPTF.PNG

N₂F₂ 3D view


Vibrational analysis and IR spectrum

Data

Mode 1 2 3 4 5 6
Wavenumber (cm-1) 348 561 772 949 987 1637
Symmetry A1 A2 B2 A1 B2 A1
Intensity 1 0 75 75 81 21

AH N2F2 OPTF POP IR.PNG

  • The 3N-6 rule gives us an expected 6 vibrations (3 × 4 - 6 = 6).
  • There are only 4 peaks on the IR spectrum because two of the vibrational modes have a negligible change in dipole moment, so they are not visible via IR spectroscopy.
  • Vibrational mode 3 represents the asymmetric N-F stretching vibration.
  • The highest energy mode is the N=N stretching vibration.

Charge distribution

cis-N2F2 has a charge separation driven by the high electronegativity of the fluorine atoms.

Atom N F
Charge (e) +0.22 -0.22

AH N2F2 OPTF CDISTCONFIG.PNG

AH N2F2 OPTF POP CHARGEDIST.png

Molecular orbital analysis

  • MOs 1-4 correspond to the core orbitals of the atoms.

Molecular Orbital 9

The 9th molecular orbital of cis-N2F2 can be represented as the in-phase addition of the pz orbitals on the N and F atoms.

AH N2F2 OPTF POP MO9.PNGAH N2F2 OPTF POP LCAO.jpg

BH3

Calculation Data

Optimisation of BH3 was performed using the following parameters:

Log file AH_bh3_opt.log
Molecule BH3
Method RB3LYP
Basis set 6-31G(d,p)
Final energy -26.61532 au
RMS gradient 0.000002
Point group D3h

Log File

Media:AH_BH3_OPT.LOG

Convergence data

The following data was collected from the log file, confirming convergence.

Item table

         Item               Value     Threshold  Converged?
 Maximum Force            0.000004     0.000015     YES
 RMS     Force            0.000003     0.000010     YES
 Maximum Displacement     0.000017     0.000060     YES
 RMS     Displacement     0.000011     0.000040     YES

Low frequencies

 Low frequencies ---  -11.6940  -11.6861   -6.5543    0.0007    0.0280    0.4289
 Low frequencies --- 1162.9745 1213.1390 1213.1392

Rounded to accurate significant figures: 

 Low frequencies ---  -12  -12   -7    0    0    0
 Low frequencies --- 1163 1213 1213

Optimised molecule

Molecule parameters

  • r(B-H): 1.192Â
  • θ(H-B-H): 120.0°

Molecular structure

BH3 2D view

AH BH3 OPTF.png

BH₃ 3D view

NH3BH3

Calculation Data

Optimisation of NH3BH3 was performed using the following parameters:

Log file AH_bh3_opt.log
Molecule BH3
Method RB3LYP
Basis set 6-31G(d,p)
Final energy -83.22469 au
RMS gradient 0.000001
Point group C3v

Log File

Media:AH_NH3BH3_OPTF.LOG

Convergence data

The following data was collected from the log file, confirming convergence.

Item table

         Item               Value     Threshold  Converged?
 Maximum Force            0.000002     0.000015     YES
 RMS     Force            0.000001     0.000010     YES
 Maximum Displacement     0.000017     0.000060     YES
 RMS     Displacement     0.000008     0.000040     YES

Low frequencies

 Low frequencies ---   -5.4185   -0.3223   -0.0476   -0.0003    1.1368    1.2200
 Low frequencies ---  263.2927  632.9711  638.4651

Rounded to accurate significant figures: 

 Low frequencies ---   -5    0    0    0    1    1
 Low frequencies ---  263  633  638

Optimised molecule

Molecule parameters

  • r(B-H): 1.210Â
  • r(N-H): 1.018Â
  • r(B-N): 1.668Â
  • θ(H-B-H): 113.9°
  • θ(H-N-H): 107.9°
  • θ(N-B-H): 104.6°
  • θ(B-N-H): 111.0°
  • θ(H-B-N-H): 60.0°

Molecular structure

BH3 2D view

AH NH3BH3 OPTF.png

BH₃ 3D view

NH3-BH3 association energy

The energies of NH3BH3 and its substituent fragments are as follows:

Molecule E (AU)
NH3 -56.55777
BH3 -26.61532
NH3BH3 -83.22469

From this, we find the association energy: ΔE = E(NH3BH3) - E(NH3) - E(BH3) = -0.05160 AU = -135kJ/mol

Me3NHCl

Calculation Data

Optimisation of Me3NHCl was performed using the following parameters:

Log file AH_Me3NHCl_optf.log
Molecule Me3NHCl
Method RB3LYP
Basis set 3-21G
Final energy -632.16208
RMS gradient 0.000007
Point group C1

Log File

Media:AH_ME3NHCL_OPTF.LOG

Convergence data

The following data was collected from the log file, confirming convergence.

Item table

         Item               Value     Threshold  Converged?
 Maximum Force            0.000020     0.000450     YES
 RMS     Force            0.000004     0.000300     YES
 Maximum Displacement     0.001396     0.001800     YES
 RMS     Displacement     0.000356     0.001200     YES

Low frequencies

 Low frequencies ---   -3.8137   -1.4370   -0.0040   -0.0040   -0.0031    6.6293
 Low frequencies ---   55.9908   57.0177  190.1670

Rounded to accurate significant figures: 

 Low frequencies ---   -4   -1    0    0    0    7
 Low frequencies ---   56   57  190

Optimised molecule

Molecule parameters

  • r(N-H): 1.164Â
  • r(N-C): 1.504Â
  • r(C-H): 1.091Â
  • r(N-Cl): 2.902Â
  • θ(H-N-C): 106.3°
  • θ(N-C-H): 108.1°
  • θ(H-C-H): 109.1°

Molecular structure

Me3NHCl view

AH Me3NHCl OPTF.png

Me₃NHCl 3D view

Rigid scan

A rigid scan was performed, measuring the potential energy curve produced by increasing the N-H bond length from 0.8Â to 2.1Â in 0.1Â steps.

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