Comparison study of CC and CH vibration frequencies and eelectronic properties for mono, Di, Tri, and tetra-rings layer of arm chair (SWCNTs)

Huda N Al-Ani

doi:10.30723/ijp.v11i20.386

Abstract

Semi-empirical methods were applied for calculating the vibration frequencies and IR absorption intensities for normal coordinates of the {mono (C56H28), di (C84H28), tri (C112H28) and tetra (C140H28)} -rings layer for (7,7) armchair single wall carbon nanotube at their equilibrium geometries which were all found to have D7d symmetry point group. Assignment of the modes of vibration (3N-6) was done depending on the pictures of their modes by applying (Gaussian 03) program. Comparison of the vibration frequencies of (mono, di, tri and tetra) rings layer which are active in IR, and inactive in Ramman spectra. For C-H stretching vibrations, the results showed that vibration frequencies value increased with increased of length nano tube (rings layer SWCNT). The results include the relation for axial bonds, which are the vertical C-C bonds (annular bonds) in the rings and for circumferential bonds which are the outer ring bonds. Also include the assignment of puckering, breathing and clock-anticlockwise bending vibrations. They allow a comparative view of the charge density at the carbon atom too.

Highlights

Carbon nanotubes have been intensively studied due to their importance as building block in nanotechnology
For C-H stretching vibrations, the results showed that vibration frequencies value increased with increased of length nano tube
Include the assignment of puckering, breathing and clock-anticlockwise bending vibrations. They allow a comparative view of the charge density at the carbon atom too

Summary

Key words

Semi-empirical methods were applied for calculating the SWCNT single wall vibration frequencies and IR absorption intensities for normal coordinates of the {mono (C56H28), di (C84H28), tri (C112H28) and tetra (C140H28)} -rings layer for (7,7) armchair single wall carbon nanotube at their equilibrium geometries which were all found to have D7d symmetry point group. For C-H stretching vibrations, the results showed that vibration frequencies value increased with increased of length nano tube (rings layer SWCNT). Include the assignment of puckering, breathing and clock-anticlockwise bending vibrations. They allow a comparative view of the charge density at the carbon atom too. ‫لجميع‬, ‫تم تطبيق طرائق الحسابات شبه التجريبية لحساب ترددات الاهتزاز وشدد امتصاص الاشعة تحت الحمراء‬ ‫)الطبقات الحلقية‬C140H28)‫( ورباعي‬C112H28)‫( وثلاثي‬C84H28)‫( وثنائي‬C56H28)‫الاحداثيات الداخلية لجزيئات( احادي‬ ‫ لانابيب النانو كاربون على وفق الشكل الهندسي المتوازن والتي وجد امتلاكها للتماثل‬arm chair 7,7 ‫لانابيب من نوع‬ ‫((ومناقشتها تماثليا و تأصريا على وفق الشكل‬3N–6)) ‫اعتمد حساب الانماط الاهتزازية وبعددها‬.‫( لها لمجموعة النقطة‬D7d) ‫ وتم مقارنة ترددات الانماط الاهتزازية لهذه الجزيئات الفعالة في طيف‬.3002 ‫الهندسي التوازني لها باستعمال برنامج كاوس‬ ‫ وجد ان قيم ترددات الأنماط‬C-H ‫ بالنسبة لترددات مط الاصرة‬, ‫ والغير فعاله في طيف الرامان‬IR‫الأشعة تحت الحمراء‬ ‫ النتائج تضمنت العلاقة بين اطوال‬.‫ طول الانبوب الاحادي الطبقة (عدد الطبقات الحلقية) للجزيئات‬,‫الاهتزازية تعتمد على‬ ‫ المتجه على طول محيط انبوب‬C-C ‫ المتجه على طول المحور السيني كذلك اطوال اواصر‬C-Caxial ‫الاواصر‬ ‫ الطبقة كما تم وبدقة تعيين جميع ألانماط الاهتزازية العائدة للحركات الانبعاجية و التنفسية‬.C-Cc ‫النانوكاربون أحادي الطبقة‬ ‫ وتم حساب ودراسة‬,‫ و التي تعود اليها التشوهات الحاصلة من جراء الاهتزاز‬,‫والانحنائية باتجاه وعكس اتجاه عقرب الساعة‬

Introduction

Results and Discussion

Arm Chair

Conclusions