Physicists have phase precursor metallic hydrogen – N + 1

Presentation of the artist on the work of the diamond anvil

Image: Philip Dalladay-Simpson and Eugene Gregoryanz

Physicists from the University of Edinburgh received a new phase of ultra-high-pressure hydrogen – “phase-V». According to scientists, it is observed weakening of the hydrogen-hydrogen and perhaps it is the transition state to the phase of metallic hydrogen. Transition is observed at a pressure of 3.25 million atmospheres – pressure such presumably exist in the center of the Earth. The study is published in the journal Nature .

The authors used to achieve such pressure diamond anvil, in which between two diamonds put hydrogen gas, and then it gradually squeezed up to 3.8 million atmospheres of pressure. Due to the transparency of the material of the anvil, the compressed material was available for the study of optical methods – Raman spectroscopy. This method allows to determine the vibrational characteristics of molecules and, in particular, information about its chemical bonds.

The physicists watched the changing appearance of the Raman spectra as a function of the applied pressure. It was found that at pressures above 325 GPa begins to lose the intensity spectrum of one of the peaks – evidence that changing the electronic structure of the hydrogen molecule. New phase of scientists assigned the number «V».

According to the authors, observations suggest that in this state there is a weakening connection of hydrogen-hydrogen and the transition from the molecular structure of the substance to the metal. For a more detailed description of the phase-V needed further experiments at high pressures. In particular, we hope to determine the boundaries of existence of the phases, as well as to establish communication between the new state of hydrogen and its metallization.

The hypothetical state of metallic hydrogen was predicted as early as 1935 and has still not been received, despite numerous Messages of different research groups (which were later disproved). It is believed that due to the destruction of the material takes place at pressures of about four million atmospheres. For metallic hydrogen scientists predict unusual properties – including superconductivity and superfluidity in the simultaneous presence of an external magnetic field. It is interesting to note that the predicted critical temperature of the superconducting transition for the material – about minus 30ºC.