Difference between revisions of "Ibarramyes"
Ibarramyes (talk | contribs) |
|||
| Line 1: | Line 1: | ||
| + | ==lab marking== | ||
| + | You have a good working wiki. It would be good if you round off reported values to correct significant figures and report values of wavenumber in your answers as well. If you have any specific questions, do email Prof. Hunt | ||
| + | |||
==NH<sub>3</sub> Molecule== | ==NH<sub>3</sub> Molecule== | ||
===calculation data=== | ===calculation data=== | ||
Revision as of 01:58, 7 May 2026
Contents
lab marking
You have a good working wiki. It would be good if you round off reported values to correct significant figures and report values of wavenumber in your answers as well. If you have any specific questions, do email Prof. Hunt
NH3 Molecule
calculation data
| Name of submitted log file | NH3_OPTF_POP_MI_CHEM307.LOG |
| Molecule | NH3 |
| Method | RB3LYP |
| Basis set | 6-31G(d,p) |
| Final energy | -56.557769 |
| RMS gradient | 1.53e-07 |
| Point group | C3v |
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
Optimized molecule image
Jmol rotatable molecule
logfile: Media:NH3_OPTF_POP_MI_CHEM307.LOG
Optimized NH molecule |
Important geometric parameters
Optimized bond distance and angle for NH3
r(N-H)=1.018Â
θ (H-N-H)=106°
Logfile Information
Low frequencies --- -5.6864 -3.6131 -3.6124 -0.0014 0.0045 0.0162 Low frequencies --- 1089.3674 1693.9284 1693.9284
| Mode | 1 | 2 | 3 | 4 | 5 | 6 |
| wavenumber(cm-1) | 1089 | 1693 | 1693 | 3461 | 3589 | 3589 |
| Symmetry | A1 | E | E | A1 | E | E |
| intensity(arbitrary units) | 145 | 14 | 14 | 1 | 0.3 | 0.3 |
IR Spectrum of NH3
Charge Analysis of NH3
| Atom | charge |
| N | 0.375 |
| H | -1.125 |
N2F2 Molecule
Calculation Data
| Name of submitted log file | MI_N2F2_OPTF_POP_CHEM307.LOG |
| Molecule | N2F2 |
| Method | RB3LYP |
| Basis set | 6-31G(d,p) |
| Final energy | -309.01241 |
| RMS gradient | 3.17e-07 |
| Point group | C2v |
Item Table and Low Frequencies
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 --- 0.0005 0.0005 0.0013 3.2233 4.3533 5.0998 Low frequencies --- 347.8772 561.2472 771.6105
Optimized molecule image
Jmol rotatable molecule
logfile: Media:MI_N2F2_OPTF_POP_CHEM307.LOG
Optimized NF molecule |
Important geometric parameters
Optimized bond distance and angle for N2F2
r(N-F)=1.391Â
r(N=N)1.220Â
θ (F-N=N)=35°
Logfile Information
| Mode | 1 | 2 | 3 | 4 | 5 | 6 |
| wavenumber(cm-1) | 348 | 561 | 772 | 949 | 987 | 1637 |
| Symmetry | A1 | A2 | B2 | A1 | B2 | A1 |
| intensity(arbitrary units) | 0.6 | 0 | 75 | 75 | 81 | 21 |
IR Spectrum of N2F2
Charge Analysis of N2F2
| Atom | charge |
| N | 0.215 |
| F | -0.215 |
Molecular Orbitals
Additional Questions about N2F2
Q. How many vibrations are expected from the 3N-6 rule?
A. N2F2 has 4 atoms, therefore 3(4)-6=6; so 6 vibrations are expected.
Q. Why are there only 4 peaks in the IR spectrum?
A. There are 6 vibrational modes but due to its symmetry, some modes have 0 intensity. Only the modes that can change the dipole moment will appear visible on the IR spectrum.
Q. Which vibration is the asymmetric N-F stretch?
A. The vibration at 949cm-1
Q. What is the nature of the highest energy vibration
A. The N=N stretch
Q. Which MOs are core orbital MOs?
A. MO 1 and MO 2 are for the S orbitals for the F, and MO 3 and MO 4 for the S orbitals for the N
