TubeGen Online

TubeGen Online - Version 3.4
Web-Accessible Nanotube Structure Generator

TubeGen was developed with the financial support of the National Science Foundation and is made available by the Doren Research Group, Department of Chemistry & Biochemistry at the University of Delaware.

If you use the structures generated via this page in publications and/or presentations, please include an appropriate citation:

TubeGen 3.4 (web-interface, http://turin.nss.udel.edu/research/tubegenonline.html), J. T. Frey and D. J. Doren, University of Delaware, Newark DE, 2011.

This version of TubeGen Online uses version 3.4 of the TubeGen utility, which is available as source code; the code compiles on many flavors of Linux, SGI's IRIX operating system, as well as Mac OS X (several users have also gotten it to work under Windows). If you want the source code you should email me and request a username and password for my Subversion repository.

PLEASE NOTE!

The calculations involved in generating these structures are performed on a machine tasked with many other chores (including serving this web site). To keep the machine responsive and available, the chirality and propogation values have limits imposed on them as indicated.

Chirality (n,m):	(,)
Atomic Basis¹:	{,}
Bond Length²:	Å
Crystal Cell³:
Cell Gutter in (a1,a2,a3) directions⁴:	,,Å
Cell Replication Count in (i,j,k)⁵:	,,
Format⁶:
Units:
Adjust Rolled-Tubule Bond Lengths⁷:
Verbose Output⁸:

You may specify chemical symbols or atomic numbers in these fields.
Default carbon-carbon bond length (in angstrom): Dresselhaus, M. S., Dresselhaus, G., Eklund, P. C. "Science of Fullerenes and Carbon Nanotubes" Academic Press: San Diego, CA, 1995; pp. 760.
Imagining this program cuts a single-layer, finite-dimension chunk out of a graphene sheet, the rolled lattices represent rolling that chunk into a tubular structure. The flat lattice implies that the chunk is not rolled, but output as a sheet-like structure (useful for tight-binding calculations, for instance). The two types of rolled lattices reflect the type of crystal cell used: hexagon close-packed or a body-centered cubic cell.
The "cell gutter" is the amount of free space to allocate on each side of the atomic basis. In essence, for the rolled lattices, twice this distance is the intertubule distance. Each coordinate direction of the crystal cell has an independent amount of padding; physically-speaking, you should keep the padding in the a1 and a2 directions equal while using no gutter in the a3 direction. Values are in Angstroms; the default reflects the standard interlayer spacing in graphite.
Propogation of the cell is only used when outputting a Gaussian com file. The cell is replicated i times in the a1 direction, j times in the a2 direction, and k times in the a3 direction. Useful for generating Gaussian input files with bundles (i,j > 1) of nanotubes or for extending the length of a nanotube (k > 1).
Output to a WIEN struct file is always in fractional coordinates; output to Gaussian com file is always in Cartesian coordinates with the structure centered at the origin. The second Gaussian and PDB file formats add periodic boundary condition (PBC) information to the output file (Gaussian '03 and PDB v2).
When TubeGen creates a rolled nanotube structure, it originally wrapped the graphitic chunk around a cylinder of fixed size. In the process, C-C bonds are stretched and compressed by the nature of the algorithm used, resulting in a set of nearest-neighbor bond lengths that average to the given C-C bond length, but are not all of that length. Version 3.0.6 added a segment of code which accounts for this expansion/compression to produce correct C-C bond lengths in the rolled nanotubes; for backwards compatibility, you may revert to the original uncorrected method by unchecking this option.
As it generates the atomic basis for the crystal cell, TubeGen can display various structural parameters (e.g. tubule radius, number of hexagonal sub-cells, chiral vector) that can be useful.