We use a pseudopotential model to calculate the electronic states available to an excess electron in crystalline and amorphous regions of model polyethlyene as well as the molecular crystal of the linear alkane C27H56. It is shown that alkane crystals of whatever chain length are not representative of crystalline polyethylene (PE) although they are often considered to be so. We discuss the implications for electron transport in PE. (C) 2003 Elsevier Science B.V. All rights reserved.