High pressure Raman spectra of n-octane were investigated by diamond anvil cell (DAC) at pressure up to 7 GPa and ambient temperature. The result shows that the liquid-solid phase transition of n-octane takes place around 0.8 GPa. Within the experimental pressure range, the Raman shift of n-octane moves to higher frequency, while the peak intensity decreases, and the width of peaks broaden with increasing pressure. A turning point is observed in the curve of pressure-dependent Raman shift when the pressure increases up to 6.8 GPa. This result indicates that a solid-solid phase transition for n-octane has been finished at this pressure. The pressure-induced phase transition pressure in alkanes decreases with the length of their chains increasing.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |