Linear scaling algorithm for the coordinate transformation problem of molecular geometry optimization

This article presents a new algorithm to solve the coordinate transformatio n problem of molecular geometry optimization. The algorithm is very fast an d its CPU time consumption scales linearly with the system size. It makes u se of the locality of internal coordinates by efficient sparse matrix techn iques. The new algorithm drastically reduces the time needed for coordinate transformations as demonstrated by test calculations on polyalanine and ca rbone nanotube systems: for a 2000 atom system it requires just seven secon ds, instead of the hours consumed by traditional schemes. (C) 2000 American Institute of Physics. [S0021- 9606(00)30738-3].