The program "MPorphW"

Program Manual

The program implements a simple Hückel MO and spin density calculation (see Theory). The program has four tabs and a menu.

1. Tab "Info"

This tab is displayed at start up and contains the program title and general information. The picture located here is a screen shot of the DOS program "MPorph", an ancestor of the current program.

At start up the last saved molecule is automatically loaded.

Another molecule can be loaded at this point: Menu File Open.

2. Tab "Design"

The following functions are currently available.

2.1. Molecule orientation change

45° counterclockwise rotation: Menu Molecule Rotate L 45
45° clockwise rotation: Menu Molecule Rotate R 45
180° rotation around the xy-diagonal: Menu Molecule Flip Molecule

2.2. Atomic data modification

Select an atom by clicking or by choosing an atomic number in the edit box at the right-hand panel. The atomic information is displayed in the table.
Right-click on the molecule window or on the table. A pop-up menu with the modification choices will appear.

Atomic Information
Name	Atom label (any description)
Type	Pi-atom type ("0" denotes non Pi-atom)
Group	The group name that the atom belong to.
Alpha	AO level (in units of \|BetaCC\| )
Q-factor	McConnell spin factor
Delta shift	The additional NMR shift (e.g. due to the attached substituents)
Line color	The color of the NMR line in the spectrum
Atom index	The number of the atom in the molecule (calculated automatically)
AO index	The number of an atomic orbital associated with the atom
Show line	The display flag of the line in the NMR spectrum

2.3. Atom addition and deletion: Right-click Add Atom Add Direct (if the selected atom has two bonds) or Add Left / Right (if the atom has one bond). For example:


Select C ₀	Add Atom Add Direct C ₁ is added	Add Atom Add Right C ₂ is added

By default a carbon atom is added.

For addition of an atom with an arbitrary angle: Right-click Add Atom Add Angle Enter the angle value. The angle 60° corresponds to "Add Left" and the angle -60° corresponds to "Add Right"

2.3. Bond modification

Select two items by holding Ctrl and Clicking.
Right-click on the molecule window (not on an atom) Pi Bond Toggle. This toggles Creation/Destruction of a bond.

3. Tab "Complex"

Complex creation and MO display.

The central windows displays the current MO. The right panel displays the energy structure of the molecule.

Available functionality

The button "Create Complex" creates the designed complex
For adjustment of the number of alpha and beta pi-electrons use the spin edits on the left panel.
For modification of the Metal-Nitrogen resonance parameter use the "Beta M-N" edit box.
To change the atom captions use the "Display" selection group (it affects both the Design and Complex tabs).
The right panel displays the energy spectrum of the complex. The current MO level is shown in red color. The metal level is shown in black. To navigate through the molecular orbitals change the "MO" spin-edit.
The slide bars at the bottom control axial ligands rotation.

4. Tab "Spectrum"

The NMR lines are plotted as lines of the colors selected at the design stage. The lines are labeled with the corresponding atom names.

The picture at the right panel displays spin density distribution in the molecule.

The line positions of atom a are calculated according to the following formula

LinePosition _a := QFactor_a*SpinDensity_a + DeltaShift_a + RhombicShift*Cos(2*Angle _a);

where the Angle_a depends on the type of g-tensor rotation described below

g-tensor rotation type	Angle_a
No rotation	(Atom Angle)_a - (Rhombic Angle)₀
Co-rotation	(Atom Angle)_a - (Rhombic Angle)₀ - (Axial Angle)
Counter-rotation	(Atom Angle)_a - (Rhombic Angle)₀ + (Axial Angle)

Here (Atom Angle)_a is the angle of atom a relative to the molecular x-axis; (Rhombic Angle)₀ is the direction of the g-tensor principal axes at the initial orientation of the axial ligands, (Axial Angle).


(Axial Angle) = 0, (Rhombic Angle)₀ = 0	(Axial Angle) > 0, g-tensor co-rotation	(Axial Angle) > 0, g-tensor counter-rotation

McConnell spin factors

Atom	Position	Q-Factor
H	.C-H	-496.8
H	.C-CH₃	+591.4
C	¹³C.	-1223.0

Menu

File
- Load
- Save
- Save As
Molecule
- Rotate L 45 - 45° counterclockwise rotation
- Rotate R 45 - 45° clockwise rotation
- Flip - 180± rotation around the xy-diagonal
- Del Group - Delete atomic group (not yet implemented)
Complex
- Show H - Hamiltonian display (see Display Forms below)
- Show E, C - Energy and MO coefficients display
- Spin Dens -Spin Density display
- Electr Pop - Electron population display
Spectrum
- Rhombic Shift - Rhombic shift entry
- Rhombic Angle - Rhombic angle entry
- Line Positions - Line position display. It can be used for the setting of Left/Right Limits on the Spectrum tab.
Copy
- MO Picture - copies the MO picture into the clipboard. The picture can be pasted into documents or graph editors.
- Spectrum - copies the spectrum picture into the clipboard.
Help
- Help
- Doc
- About

Display Forms

Several menu items launch the display forms.

Some of the forms can be used for direct editing. If the "M" button is pressed then all changes will be saved when closing the form.