QuantumATK Forum

QuantumATK => General Questions and Answers => Topic started by: Hasan Sahin on August 12, 2010, 19:07

Title: Why Molecular Orbital is visualised same in VNL for different options ?
Post by: Hasan Sahin on August 12, 2010, 19:07

Hello,

I plot HOMO and LUMO levels within VNL. Different options of VNL such as sign, magnitude and value yield same isosurface (only the color format is changed). Why are they same, what is the definition ? What do we visualize in vnl ?

Title: Re: Why Molecular Orbital is visualised same in VNL for different options ?
Post by: Anders Blom on August 12, 2010, 19:34

Of course - since the options you mention are labeled "Color by...", only the color changes when you choose different ones :)

To change the actual isosurface you will have to change the isovalue.

The three choices you mention mean whether the colormap should apply to the values of [tex]\Psi({\mathbf r})[/tex], the magnitude (i.e. we don't care about the sign, just the value of [tex]|\Psi(\mathbf{r})|[/tex]) or the sign (we don't care about the values, just whether [tex]\Psi(\mathbf{r})>0[/tex] or [tex]\Psi(\mathbf{r})<0[/tex]).

The isosurface itself represents all the points where [tex]\Psi(\mathbf{r})=[/tex] the isovalue, unless you also choose the "Absolute" option in which case you plot the points where [tex]|\Psi(\mathbf{r})|=[/tex] the isovalue.