Quantum optimal control of HCN isomerization

Quantum optimal control of HCN isomerization is studied including all vibrational degrees of freedom and with rotation treated in the sudden approximation. The nuclear dynamics toolkit (NDT) technique is used for solving the control equations. The NDT is shown to be successful in reducing the computational expense in the large-scale optimal control calculations by shifting the resource burden from the processor to the storage. The C-N stretching mode was found to be important in the isomerization dynamics. Modest isomerization yields were found when keeping the field intensity below levels, where severe electronic disturbances could occur. Significant molecular orientational dependence upon the yield is found, with some orientations producing high yields while others giving little product when exposed to a single optimal field. (c) 2006 Elsevier B.V. All rights reserved.