# Geometry

Dear all,

Is there a reference list to show the initial value of the

• bond length between 2 atoms? (e.g what is the bond length between the
pairs of atom (a, b), (c, d) (a, e) and etc. What is the minimum and
maximum value of the bond length?)

• angle between 3 atoms? (e.g what is the angle between atom (a, b, c),
(c, d, e), (a, e, j) and etc).

• torsion between 4 atoms? (e.g what is the torsion between atom (a, b, c,
d), (c, d, e, g), (a, e, j, k) and etc).

I need the above values to fill up a Z-matrix table and to create a
Z-matrix program so that I can input the information of a structure. If
the bond lengths and the angles are fixed, what parameters do I need to
calculate the torsion angles and to vary the torsion angles?

Are there any files and source codes in Avogadro distribution related to
my questions?

Thanks & regards,

Sandy

Hi Sandy,

Sorry for the late reply! It seems the community has been busy with

On Wed, Dec 21, 2011 at 3:17 AM, Sandy limsm55@gmail.com wrote:

Is there a reference list to show the initial value of the

• bond length between 2 atoms?
• angle between 3 atoms?
• torsion between 4 atoms?

I need the above values to fill up a Z-matrix table and to create a Z-matrix
program so that I can input the information of a structure. If the bond
lengths and the angles are fixed, what parameters do I need to calculate the
torsion angles and to vary the torsion angles?

Are there any files and source codes in Avogadro distribution related to my
questions?

There was a start on a z-matrix editor a while back, but I donâ€™t
believe that it was completed. For now, you can measure the bond
lengths, angles, and torsion/dihedral angles with the Measure tool.
There is also a roundabout way to get a full z-matrix:

Extensions > Gaussian > Format: Z-matrix

The z-matrix will be in the text field of the dialog window.

Hope this helps,

Dave