Ab initio modelling of K-alpha X-ray spectra in single walled carbon nanotubes

New technologies are currently being developed that require the alignment of carbon nanotube arrays. However, the measurement of carbon nanotube alignment is difficult, especially with micron spatial resolution. Here we consider the use of soft X-ray spectroscopy to measure alignment and we present theoretical electronic density of states (DOS) calculations which show this is possible. To verify the DOS calculations we compare the predicted DOS of graphite and C60 with experimentally measured carbon K,, spectra. In addition we examine a range of electron exchange and correlation functionals to find the optimal one for predicting soft X-ray peak shape and position.