کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
10393221 | 887760 | 2005 | 5 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Correlation between MO eigenvectors and enthalpies of formation for alkanes
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موضوعات مرتبط
مهندسی و علوم پایه
مهندسی شیمی
جریان سیال و فرایندهای انتقال
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
A new model for the calculation of enthalpies of formation of alkanes (up to C8) is presented. An additive bond energy scheme, using the experimental methane and diamond values for the CH and CC bond energies, respectively, is supplemented by correction for the CC Ï antibonding character of the highest occupied molecular orbitals (HOMOs), effectively adjusting the CC bond energies. The effect is calculated by the summation of products of appropriate eigenvectors from semiempirical PM3 or HF/STO-3G calculations, after orthogonal transformation. The enthalpy of formation can then be expressed in terms of only one adjustable parameter. With HF/STO-3G eigenvectors, the mean discrepancy between experimental and calculated enthalpies of formation, after a one-parameter correction for 1,4 steric interactions, is 2.2Â kJÂ molâ1, comparable with more highly parameterized models. The results using PM3 eigenvectors are less satisfactory, probably on account of the neglect of overlap in the semiempirical scheme.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Thermochimica Acta - Volume 435, Issue 1, 1 September 2005, Pages 44-48
Journal: Thermochimica Acta - Volume 435, Issue 1, 1 September 2005, Pages 44-48
نویسندگان
Matthew C.J. Lee, Derek W. Smith,