Binding of NH3 to graphite and to a (9,0) carbon nanotube -: art. no. 115409

The interaction of NH3 with graphite and a (9,0) carbon nanotube is studied using the second-order Moller-Plesset and density functional theory approaches. For both graphite and the nanotube, our best estimate of the NH3 binding energy is 2+/-2 kcal/mol. NH3 physisorbs on the carbon surface and the hydrogen end points toward the carbon surface. The binding is mostly electrostatic in nature and there is very little charge transfer occurring. Band-structure calculations on a (10,0) semiconducting nanotube show essentially no change in the nanotube band gap when NH3 is added. The implications of these calculations on the experimental results are discussed.