THE WRITHE OF A SELF-AVOIDING WALK

The writhe of a self-avoiding walk in a three-dimensional space is the average over all projections onto a plane of the sum of the signed cr ossings. We compute this number using a Monte Carlo simulation. Our re sults suggest that the average of the absolute value of the writhe of self-avoiding walks increases as n(alpha), where n is the length of th e walks and alpha almost-equal-to 0.5. The mean crossing number of wal ks is also computed and found to have a power-law dependence on the le ngth of the walks. In addition, we consider the effects of solvent qua lity on the writhe and mean crossing number of walks.