دراسة ترددات الاهتزاز و شدد امتصاص الأشعة تحت الحمراء لمركب البنزين ثلاثي البيوتان الحلقي وتعيين طاقة نواتج تكسره الحراري إلى مركب الراديالين السداسي المستوي باستخدام حسابات مكانيك الكم

Abstract

AbstractMINDO/3-FORCES, PM3 and ab initio calculations were carried out for the vibration frequencies, IR absorption intensities and normal coordinates of the tricyclobutabenzene (D3h) compound at its calculated equilibrium geometry. Assignment of the modes of vibration (3N-6) was done depending on the picture of their modes drawn applying the DRAW. MOL routine. The potential energy curve for thermal cracking of tricyclobutabenzene compound was obtained by changing the distance of the terminal C-C bonds of the cyclobutane rings using semiemperical quantum mechanical method (PM3) to find the reaction path. The thermal cracking results of tricyclobutabenzene compound was converted it to the planar 6-Radialine (D3h) compound which had the higher energy and less stable than the tricyclobutabenzene compound.Interesting relations between the different modes of the IR calculation spectra were also was found on inspecting their frequencies. CH str. (planar 6-Radialine) > CH str. (tricyclobutabenzene)CH str.(symmetric) > CH str. (asymmetric) CC str.(asymmetric) > CC str.(symmetric)δ(CH2 (scissoring)) > δ(CH2 (rocking)) (CH2 (waging)) >  (CH2 (twisting))δ (CC) >  (CC)