# Orbital Modify

- Type
- Scope
- Volume
- Position
- View

Change here the position and orientation for a single orbital or a list of orbitals.

To modify an orbital, click over its graphic image, or write its id on the Orbital entry. To modify a list of orbitals, press the button List (after creating the list of orbitals with Orbital->Select). Parameters for empty entries or Local choices remain unchanged.

To change an orbital name write the new name in the Orbital entry, followed by the orbital number (GAMGI needs the number to identify the orbital). To change the name for a list of orbitals, press List first and then write the new common name in the Name entry.

### Translation

The origin of an orbital object, defined as its center, can be set using the X, Y, Z entries. A simpler way to set directly the orbital position is to click on the screen, at the wished position, after defining all the other orbital properties: a new orbital object is created at that position.

### Rotation

The orientation of an orbital object, defined by the Euler angles theta, phi, psi, can be set using the E1, E2, E3 entries.

Euler angles in GAMGI are defined as follows: first, the (x, y, z) referential is rotated theta degrees (between 0 and 180) around the y axis, then the referential is rotated phi degrees (between 0 and 360) around the initial z axis, and finally it is rotated psi degrees (between 0 and 360) around the new z axis, always in the direct, counter-clockwise, direction. If the first Euler angle (theta) is zero, the old and new z axis coincide, thus (0, 0, 10) and (0, 5, 5) represent the same rotation.

By default, the orbital frame first vector is aligned with the x axis (to the right), the second vector is on the xy (screen) plane and the third vector has a positive z coordinate (pointing to the user), corresponding to Euler angles (0, 0, 0).
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