Wolfeka

NH₃ molecule

Calculation data

name of submitted log file	KATW307_nh3opt1.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            0.000002     0.000015     YES
 RMS     Force            0.000001     0.000010     YES
 Maximum Displacement     0.000010     0.000060     YES
 RMS     Displacement     0.000006     0.000040     YES

Key bond distances and angles

r(N-H) bond distance	1.02Â
θ(H-N-H) bond angle	106°

Optimised molecule image

File history

Media:KATW307 NH3OPT1.LOG

3D NH molecule

 Low frequencies ---   -5.6864   -3.6131   -3.6124    0.0022    0.0047    0.0163
 Low frequencies --- 1089.3674 1693.9284 1693.9284

mode	1	2	3	4	5
wavenumber (cm-1)	1089	1694	1694	3461	3590	3590
symmetry	A1	E	E	A1	E	E
intensity	145	14	14	1	0	0

NH₃ charges

Atom	Charge (e)
N	-1.13
H3	0.38

NH₃ IR spectrum

Project molecule

Calculation data

name of submitted log file	KATW307_n2f2opt1.log
molecule	N2F2
method	RB3LYP
basis set	6-31G(d,p)
final energy	-309.0124
RMS gradient	1.218e-06
point group	C2v

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

Key bond distances and angles

r(N-N) bond distance	1.22Â
r(N-F) bond distance	1.39Â
θ(N-N-F) bond angle	114°

Optimised molecule image

File history

Media:KATW307 N2F2OPT1.log

N₂F₂ frequencies

3D NH molecule

 Low frequencies ---   -0.0011    0.0008    0.0019    3.4929    4.3715    5.1621
 Low frequencies ---  347.8732  561.2460  771.6039

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)	1	0	75	75	81	21

N₂F₂ charges

Atom	Charge (e)
N2	0.22
F2	-0.22

N₂F₂ IR spectrum

Questions and answers

1. The molecule from the log file does not have bonds between the F and N atoms, what is going on here?

The program running the optimization works under an assumption of what the length of the F and N atoms should be, and since the optimization put their bond length as longer than this assumed value, the program did not include a bond there. As the atoms get closer the program will include a bond between the atoms.

2. For your IR analysis how many vibrations are expected from the 3N-6 rule?

3N-6 where N is the number of atoms would give N=4 and 3(4)-6= 6 vibrational modes, this is consistent with the number of vibrational modes obtained in the optimization as well.

3. Why are there only 4 peaks in the IR spectrum?

There are degenerate vibrational modes, the A1, A2, B1

4. For your IR analysis which vibration is the asymmetric N-F stretch? 5. For your IR analysis what is the nature of the highest energy vibration?