Rlk3917 inorganic computational

BH₃

B3LYP 6-31Gd/p

 BH3 frequency and MOs
File Name = RKW-BH3-FREQ
File Type = .log
Calculation Type = FREQ
Calculation Method = RB3LYP
Basis Set = 6-31G(d,p)
Charge = 0
Spin = Singlet
E(RB3LYP) = -26.61532348 a.u.
RMS Gradient Norm = 0.00007899 a.u.
Imaginary Freq = 0
Dipole Moment = 0.0000 Debye
Point Group = D3H
Job cpu time:       0 days  0 hours  0 minutes 36.0 seconds.

 Item               Value     Threshold  Converged?
 Maximum Force            0.000158     0.000450     YES
 RMS     Force            0.000079     0.000300     YES
 Maximum Displacement     0.000622     0.001800     YES
 RMS     Displacement     0.000311     0.001200     YES

Link to log file

 Low frequencies ---   -0.2456   -0.1129   -0.0054   44.0270   45.1846   45.1853
 Low frequencies --- 1163.6049 1213.5924 1213.5951

BH3

Vibrations

#	Frequency / cm^-1	Intensity
1	1164	92
2	1214	14
3	1214	14
4	2580	0
5	2713	126
6	2713	126

The 4th vibration is IR inactive, as this corresponds to the symmetrical stretch of all three B-H bonds.

Ng611 (talk) 17:38, 8 May 2019 (BST) Symmetry labels and assignments (i.e.: type of mode, out-of-plane bend, in-plane bend, etc.) are missing. Also, why are there only three peaks in the IR spectrum, but 6 modes in the table?

MOs

Molecular Orbital diagram from: P. Hunt's tutorial notes, http://www.huntresearchgroup.org.uk/teaching/teaching_comp_lab_year2a/Tut_MO_diagram_BH3.pdf, (accessed May 2019)

The calculated molecular orbitals do not deviate significantly from those derived through a qualitative approach, showing that it is a powerful tool for the approximate determination of molecular orbitals.

Ng611 (talk) 17:43, 8 May 2019 (BST) Note that the 3a1 and 2e' MOs have do deviate somewhat from qualitative MO theory. Try to think about how they deviate.

NH₃ & NH₃BH₃

NH₃

B3LYP 6-31Gd/p

NH3
File Name = NH3
File Type = .log
Calculation Type = FREQ
Calculation Method = RB3LYP
Basis Set = 6-31G(d,p)
Charge = 0
Spin = Singlet
E(RB3LYP) = -56.55776873 a.u.
RMS Gradient Norm = 0.00000323 a.u.
Imaginary Freq = 0
Dipole Moment = 1.8465 Debye
Point Group = C3V
Job cpu time:       0 days  0 hours  0 minutes 57.0 seconds.

Item               Value     Threshold  Converged?
 Maximum Force            0.000006     0.000450     YES
 RMS     Force            0.000004     0.000300     YES
 Maximum Displacement     0.000014     0.001800     YES
 RMS     Displacement     0.000009     0.001200     YES

Link to log file

Low frequencies ---   -0.0127   -0.0022    0.0006    7.1034    8.1048    8.1051
 Low frequencies --- 1089.3834 1693.9368 1693.9368

NH3

NH₃BH₃

B3LYP 6-31Gd/p

NH3BH3
File Name = NH3BH3
File Type = .log
Calculation Type = FREQ
Calculation Method = RB3LYP
Basis Set = 6-31G(d,p)
Charge = 0
Spin = Singlet
E(RB3LYP) = -83.22468892 a.u.
RMS Gradient Norm = 0.00005935 a.u.
Imaginary Freq = 0
Dipole Moment = 5.5651 Debye
Point Group = C3V
Job cpu time:       0 days  0 hours  0 minutes 28.0 seconds.

Item               Value     Threshold  Converged?
 Maximum Force            0.000121     0.000450     YES
 RMS     Force            0.000057     0.000300     YES
 Maximum Displacement     0.000570     0.001800     YES
 RMS     Displacement     0.000318     0.001200     YES

Link to log file

Low frequencies ---   -0.0253   -0.0031    0.0004   17.0476   17.0501   36.9367
 Low frequencies ---  265.7521  632.2129  639.3374

NH3BH3

Relative Energy

E(BH3)=-26.61532 a.u. E(NH3)=-56.55777 a.u. E(NH3BH3)=-83.22469 a.u.

ΔE=E(NH3BH3)-[E(NH3)+E(BH3)]=-83.22469-(-26.61532-56.55777) =-0.05160 a.u =-135 kJmol^-1

This is a weak bond, compared with a C-C bond in the analagous ethane which is ~360 kJmol^-1.

Ng611 (talk) 17:49, 8 May 2019 (BST) You need to add a reference here for the literature value you cited.

NI₃

B3LYP/6-31G(d,p)LANL2DZ

Link to log file

NI3 optimisation
File Name = NI3-OPTIMISATION
File Type = .log
Calculation Type = FREQ
Calculation Method = RB3LYP
Basis Set = Gen
Charge = 0
Spin = Singlet
E(RB3LYP) = -88.80858845 a.u.
RMS Gradient Norm = 0.00004431 a.u.
Imaginary Freq = 
Dipole Moment = 1.3092 Debye
Point Group = C3V
Job cpu time:       0 days  0 hours  0 minutes 27.0 seconds.

Item               Value     Threshold  Converged?
 Maximum Force            0.000102     0.000450     YES
 RMS     Force            0.000075     0.000300     YES
 Maximum Displacement     0.000858     0.001800     YES
 RMS     Displacement     0.000629     0.001200     YES

Low frequencies ---  -12.3845  -12.3781   -5.6129   -0.0040    0.0194    0.0711
 Low frequencies ---  100.9307  100.9314  147.2333

NH3BH3

N-I bond length = 2.184 Å

Project

Isomer 1

Method:B3LYP/ Al 6-31G(d,p); Cl, Br LANL2DZ

Link to log file

Al2_1
File Name = AL2_1
File Type = .log
Calculation Type = FREQ
Calculation Method = RB3LYP
Basis Set = Gen
Charge = 0
Spin = Singlet
E(RB3LYP) = -571.43283094 a.u.
RMS Gradient Norm = 0.00002738 a.u.
Imaginary Freq = 0
Dipole Moment = 0.0000 Debye
Point Group = D2H
Job cpu time:       0 days  0 hours  0 minutes 21.0 seconds.

Item               Value     Threshold  Converged?
 Maximum Force            0.000034     0.000450     YES
 RMS     Force            0.000015     0.000300     YES
 Maximum Displacement     0.000402     0.001800     YES
 RMS     Displacement     0.000113     0.001200     YES

Low frequencies ---   -2.5130   -1.5345   -0.0024   -0.0020   -0.0019    1.9565
 Low frequencies ---   16.6689   62.3371   84.7970

Al2Br2Cl4 Isomer 1

Isomer 2

Method:B3LYP/ Al 6-31G(d,p); Cl, Br LANL2DZ

Link to log file

Al2_2
File Name = Al2_2_1
File Type = .log
Calculation Type = FREQ
Calculation Method = RB3LYP
Basis Set = Gen
Charge = 0
Spin = Singlet
E(RB3LYP) = -571.43792379 a.u.
RMS Gradient Norm = 0.00013242 a.u.
Imaginary Freq = 0
Dipole Moment = 0.0276 Debye
Point Group = C1
Job cpu time:       0 days  0 hours  0 minutes 37.0 seconds.

Item               Value     Threshold  Converged?
 Maximum Force            0.000318     0.000450     YES
 RMS     Force            0.000076     0.000300     YES
 Maximum Displacement     0.000554     0.001800     YES
 RMS     Displacement     0.000243     0.001200     YES

Low frequencies ---   -3.7118   -2.2032   -0.0006    0.0009    0.0015    2.2873
 Low frequencies ---   18.7371   47.6135   71.2551

Al2Br2Cl4 Isomer 2

Relative Energy

-571.43792379 a.u.--571.43283094 a.u. = -0.00509 a.u. = -13.4 kJmol^-1

Isomer 2 is lower in energy. This is because the large bromine atoms are not the bridging species, and are not forced into close proximity causing steric clashes.

AlBrCl₂

Method:B3LYP/ Al 6-31G(d,p); Cl, Br LANL2DZ

Link to log file

Al
File Name = Al
File Type = .log
Calculation Type = FREQ
Calculation Method = RB3LYP
Basis Set = Gen
Charge = 0
Spin = Singlet
E(RB3LYP) = -285.70300759 a.u.
RMS Gradient Norm = 0.00005532 a.u.
Imaginary Freq = 0
Dipole Moment = 0.3536 Debye
Point Group = CS
Job cpu time:       0 days  0 hours  0 minutes 23.0 seconds.

Item               Value     Threshold  Converged?
 Maximum Force            0.000104     0.000450     YES
 RMS     Force            0.000063     0.000300     YES
 Maximum Displacement     0.000729     0.001800     YES
 RMS     Displacement     0.000610     0.001200     YES

Low frequencies ---   -0.0024   -0.0024   -0.0020    1.8269    2.9309    4.9652
 Low frequencies ---  119.7790  132.7679  182.5577

AlBrCl2

Dissociation Energy

ΔE = E(Al₂Br₂Cl₄) - 2 x E(AlBrCl₂) = -571.43792379 a.u. -2 x -285.70300759 a.u. = 0.03191 a.u. = -83.8 kJmol^-1

The monomer is more stable than the dimer.

Ng611 (talk) 18:07, 8 May 2019 (BST) 3x MOs were required.

Ng611 (talk) 18:07, 8 May 2019 (BST) The LCAO decomposition for your first MO is incorrect; the terminal chlorine/bromine atoms should interact via their s orbitals.

Ng611 (talk) 18:11, 8 May 2019 (BST) Second MO decomposition is good, well done.

BH3

Vibrations

MOs

NH3 & NH3BH3

NH3

NH3BH3

Relative Energy

NI3

Project

Isomer 1

Isomer 2

Relative Energy

AlBrCl2

Dissociation Energy

BH₃

NH₃ & NH₃BH₃

NH₃

NH₃BH₃

NI₃

AlBrCl₂