The estimation of the heat capacity of NpO2

✍ Scribed by Hiroyuki Serizawa; ; Yasuo Arai; ; Kunihisa Nakajima

• Publisher: Elsevier Science
• Year: 2001
• Tongue: English
• Weight: 522 KB
• Volume: 33
• Category: Article
• ISSN: 0021-9614
• DOI: 10.1006/jcht.2000.0775

✦ Synopsis

The heat capacity C p,m of NpO 2 was estimated for temperatures between 300 K and 1400 K. The C p,m was evaluated as a sum of three terms, phonon vibration C ph,m , dilation C d,m , and Schottky specific heat C s,m . The C ph,m and C d,m were calculated using the Debye temperature, Grüneisen constant and thermal expansion data obtained by hightemperature X-ray diffractometry. The coefficient of the linear thermal expansion (l.t.e.) for NpO 2 was given as a polynomial function up to T = 1573 K. The estimated C p,m was compared with that of previous studies. The present result at T = 300 K was 66.87 J • K -1

• mol -1 , which agreed well with previous results, 66.22 J • K -1 • mol -1 , measured by using calorimetry. The thermodynamic functions were given as a function of temperature.