Partially relaxed ring closure conditions for geometrical algorithm to search the conformational space for minimum energy conformations

We have reported a systematic search method, GASCOS, for open chain compoun ds. An extension to cyclic structures was recently reported. In this paper, we propose a more complete range of tolerance for some of the bond angles of the cyclic molecules studied. Specifically, we will accept that three co nsecutive bond angles associated with the ring closure condition can vary t heir values between certain previously fixed limits. We also introduce the concept of "family" which permit the "agglutination" of neighborhood config urations when their number is too large. Two small systems, cyclopentane an d cyclohexane, were chosen to illustrate the GASCOS partially relaxed ring closure method in optimizing cyclic structures. (C) 2001 Elsevier Science B .V. All rights reserved.