کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5428414 1508673 2014 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
High temperature partition functions and thermodynamic data for ammonia and phosphine
ترجمه فارسی عنوان
توابع پارتیشن با درجه حرارت بالا و داده های ترمودینامیکی برای آمونیاک و فسفین
موضوعات مرتبط
مهندسی و علوم پایه شیمی طیف سنجی
چکیده انگلیسی


- Partition functions are computed for ammonia and phosphine.
- Calculations are performed by direct summation of millions of energy levels.
- Thermodynamic properties are computed for a wide range of temperatures.

The total internal partition function of ammonia (14NH3) and phosphine (31PH3) are calculated as a function of temperature by explicit summation of 153 million (for PH3) and 7.5 million (for NH3) theoretical rotation-vibrational energy levels. High accuracy estimates are obtained for the specific heat capacity, Cp, the Gibbs enthalpy function, gef, the Helmholtz function, hcf, and the entropy, S, of gas phase molecules as a function of temperature. In order to reduce the computational costs associated with the high rotational excitations, only the A-symmetry energy levels are used above a certain threshold of the total angular momentum number J. With this approach levels are summed up to dissociation energy for values of Jmax=45 and 100 for ammonia (Emax=41 051 cm−1) and phosphine (Emax=28 839.7 cm−1), respectively. Estimates of the partition function are converged for all temperatures considered for phosphine and below 3000 K for ammonia. All other thermodynamic properties are converged to at least 2000 K for ammonia and fully converged for phosphine.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Quantitative Spectroscopy and Radiative Transfer - Volume 142, July 2014, Pages 66-74
نویسندگان
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