Comparison of Hydrogen Bonds in FH- CO and FH- OC Weakly Bound Dimer Complexes

摘要

Weakly bound dimer complexes FH - CO and FH- OC were investigated using various ab initio and density function theory (DFT) methods.This study compares the strengths of the H- C H-bond in FH- CO and the H-OH-bond in FH-OC.The energy difference between dimers,the H-bond energy,the inter-monomer distance,the inter-monomer vibration frequencies,the red shift of the HF stretching frequency,and the elongation of HF bond,all demonstrate that the H-C H-bond is stronger than the related H-OH-bond,according to all methods.The calculated Gibbs energies of the formation of the two dimers show that the weakly bound complexes are unstable at room temperature (T=298 K) and ordinary pressure (P=1 atm).However,decreasing T or increasing P monotonically decreases DELTA G and increases the related equilibrium constant,K,of their dimer formation.