Dense molecular hydrogen: Order, disorder, and localization

被引:5
作者
Hemley, RJ [1 ]
Mao, HK [1 ]
机构
[1] CARNEGIE INST WASHINGTON, CTR HIGH PRESSURE RES, WASHINGTON, DC 20005 USA
基金
美国国家科学基金会; 美国国家航空航天局;
关键词
D O I
10.1016/S0022-3093(96)00238-4
中图分类号
TQ174 [陶瓷工业]; TB3 [工程材料学];
学科分类号
0805 ; 080502 ;
摘要
Recently discovered high-pressure transitions in hydrogen isotopes (H-2, D-2 and HD) exhibit phenomena associated with order, disorder, and localization in their vibrational, rotational, and electronic excitations. Rotational disorder persists in hcp phase I to very high pressures, despite the dramatic increase in intermolecular coupling. Symmetry breaking of hcp occurs on passage into phase II with decreasing temperature, where the axis of rotational quantization adopts specific orientations. Above 150 GPa, a radical symmetry breaking occurs, which is characterized by a large increase in infrared vibron intensity, quasiclassical orientational ordering, and loss of even and odd rotational parity. Synchrotron infrared measurements reveal no evidence for intraband electronic excitations down to 0.15 eV in phase III. Metallization in the molecular solid appears to be controlled by the orientational state, and possibly by order-disorder associated with large-amplitude vibrational motion. The P-T phase diagram to 200 GPa is surprisingly rich, exhibiting both triple and tricritical points.
引用
收藏
页码:282 / 289
页数:8
相关论文
共 42 条
[1]   THE METAL-INSULATOR-TRANSITION - COMPLEXITY IN A SIMPLE SYSTEM [J].
ASHCROFT, NW .
JOURNAL OF NON-CRYSTALLINE SOLIDS, 1993, 156 :621-630
[2]  
ASHCROFT NW, 1991, MOLECULAR SYSTEMS UNDER HIGH PRESSURE, P201
[3]  
ASHCROFT NW, 1995, ELEMENTARY PROCESSES, P251
[4]  
BARANOWSKI B, 1992, POLISH J CHEM, V66, P1637
[5]   THEORY OF HIGH-PRESSURE PHASES OF HYDROGEN [J].
BARBEE, TW ;
GARCIA, A ;
COHEN, ML ;
MARTINS, JL .
PHYSICAL REVIEW LETTERS, 1989, 62 (10) :1150-1153
[6]   METALLIZATION OF SOLID HYDROGEN AT MEGABAR PRESSURES - A 1ST-PRINCIPLES QUASI-PARTICLE STUDY [J].
CHACHAM, H ;
LOUIE, SG .
PHYSICAL REVIEW LETTERS, 1991, 66 (01) :64-67
[7]   MEGABAR PRESSURE TRIPLE POINT IN SOLID DEUTERIUM [J].
CUI, LJ ;
CHEN, NH ;
JEON, SJ ;
SILVERA, IF .
PHYSICAL REVIEW LETTERS, 1994, 72 (19) :3048-3051
[8]   INFRARED PROPERTIES OF ORTHO AND MIXED-CRYSTALS OF SOLID DEUTERIUM AT MEGABAR PRESSURES AND THE QUESTION OF METALLIZATION IN THE HYDROGENS [J].
CUI, LJ ;
CHEN, NH ;
SILVERA, IF .
PHYSICAL REVIEW LETTERS, 1995, 74 (20) :4011-4014
[9]   ADDITION [J].
EGGERT, JH .
EUROPHYSICS LETTERS, 1990, 12 (04) :381-382
[10]   OBSERVATION OF A 2-VIBRON BOUND-TO-UNBOUND TRANSITION IN SOLID DEUTERIUM AT HIGH-PRESSURE [J].
EGGERT, JH ;
MAO, HK ;
HEMLEY, RJ .
PHYSICAL REVIEW LETTERS, 1993, 70 (15) :2301-2304