利用Ab Initio理論計算探討Li_3OH及Na_3OH分子的形成過程、穩定結構及能量變化

Ab Initio Theoretical Calculation to Study the Formations, Stable Structures, and Energies of Li_3OH and Na_3OH Molecules

許名智(Ming-Jyh Sheu) ； 何嘉仁(Jia-Jen Ho)

《化學》 51卷1期 (1993/03) Pp. 1-10

https://doi.org/10.6623/chem.1993001

摘要

利用Ab Initio理論計算探討Li_3OH及Na_3OH分子的生成及穩定性，發現當Li_2分子與Li-OH分子碰撞生成Li30H(C_(2v))分子時，放出了49.92 kcal/mol的熱量，而Li_3OH分子有C_(2v)平面型結槽和C_(3v)四面體結構，兩異構物間的能量差非常小，且直相轉換所須克服的能量障礙僅9.89kcal/mol因此兩異構物間可迅速轉換，且以平衡狀態存在，上述轉換過程中的過渡狀態(transition state)是以Li-O-H平面為對稱面的Cs結構(圖4)，同樣的情形也存在於Na_3OH分子，不同的是Na_3OH 分子是以C_(3v)結構較穩定，而Li_3OH分子卻是C_(2v)結構較穩定。

並列摘要

The production of Li_3OH molecule due to the collision process of Li_2 and LiOH was investigated theoretically. The association reaction energy for this process is -49.92 kcal/rnole. There are two stable structures (C_(2v) and C_(3v)) for Li_3OH molecule and the C_(2v) structure is calculated to be lower in energy. The difference between them is very small. The energy barrier of inter-conversion between these two structures is calculated to be 9.89 kcal/rnole and the transition state is also determined. Similar process was treated for the formation of Na_3OH molecule . The results showed that C_(3v) structure is lower in energy and there is also an energy barrier for the conversion to C_(2v).