We investigate the structural parameters, i.e. bond lengths and bond anglesof chiral tubes of various chiralities. The procedure used is based on helicaland rotational symmetries and Tersoff potential. The results indicate that atambient condition, there are equal bond lengths and three unequal bond anglesin the structure of chiral tubes. The bond length depends much more on thechirality and very slightly on the tube radius. Length of the tubes does notplay very significant role on bond length and bond angles. These C-C bonds wererecalculated under hydrostatic pressure. The bond length compresses withpressure while the bond angles remain practically unchanged. We also carry outanalysis regarding the cross sectional shape of chiral tubes and its pressuredependence. It is found that at some pressures, transition from circular tooval cross section takes place. The transition pressure is found to stronglydepend on the radius and chirality of tube. At this transition, correspondingto given elliptical cross section, the bond length for all chiral tubes isidentical. This behavior of bond length is different from achiral tubes.
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