THE TRUE MINIMUM ENERGY STRUCTURE OF H3SIOHALH3 - IMPLICATIONS FOR CONFORMATIONAL PREFERENCES OF BRIDGED HYDROXYL-GROUPS IN ZEOLITES

The true minimum energy conformation for H3SiOHAlH3 (a cluster model f or bridged hydroxyl groups in zeolites) is obtained using ab initio mo lecular orbital methods at the Hartree-Fock and post Hartree-Fock leve ls. It is demonstrated that previous investigations have used a first- order transition state structure. Implications for the structure and l ocation of bridged hydroxyl groups in zeolites is discussed.