煤表面对多个氧分子的多层吸附机理研究

应用密度泛函理论,在6-311水平上研究煤表面与氧的吸附作用,比较煤吸附5个氧分子,其表面与氧分子化学键的变化情况,吸附后氧分子的键变长,但不断裂,煤表面的变化很小,证明煤表面吸附5个氧分子是物理吸附,根据优化后的几何结构,证明还是多层吸附.其中侧链吸附的氧分子键长变化最大,由1.2582 A变为1.3244 A,说明侧链吸附的氧分子最活泼.从电荷集居数分析可知,原子中电子转移的多少与化学键的变化成正比,转移越多,化学键变化越大.煤表面与5个氧分子组成的吸附态中,氧分子的振动频率变小,计算其吸附能为409.68 kJ/mol.

Multilayer adsorption mechanism of coal surface adsorption to more oxygen molecule

Applied density functional theory,it had studied the adsorption of coal surface to oxygen at the 6-311 level,compared the change of coal surface and oxygen molecule chemical bonds after five oxygen molecules had been absorbed by coal,the bond of oxygen molecule became longer after adsorption,but was not broken.The change of coal surface is small,it proved that the adsorption of coal surface to five oxygen molecules was physisorption.Based on the geometry after optimization,it proved that it was also a multilayer ad- sorption.In which,bond length of oxygen molecule which was absorbed by side chain most greatly changed,from I.2582(?)to 1.3244(?).It showed that the oxygen molecule which was absorbed by side chain was the most active.It can be known from the analy- sis of charge populations,the amount of electron transfer in the atom is in the direct ratio to the change of chemical bond.The more e- lectrons transfer,the more chemical bonds are changed.In the adsorption state which is composed of coal surface and five oxygen mole- cules,vibration frequency of oxygen molecule becomes smaller,the adsorption energy is 409.68 kJ/mol by calculation.