1. prepare a xyz file for the carboxylic group, for example:
5
C -2.35369 -2.98892 0.00000
C -3.23969 -4.36579 0.00000
O -4.48139 -4.16587 0.00000
O -2.54377 -5.41329 0.00000
H -2.36337 -6.49448 -0.14573
2. Use the "Nanotube" Builder in the "Custom Builder" of VNL to create a CNT, and then transfer it into the "Builder".
3. Drag the xyz file of carbonxylic group into the "Builder" window for the created CNT.