Dynamic synthesis of crystalline carbyne from graphite and amorphous carbon

The paper deals with the effect of a shock wave generated by a laser pulse on two carbon materials, namely, pyrolytic graphite and a 10-mcm film of am orphous linear-chain carbon. The samples are irradiated by a neodymium lase r with the wavelength of 1.06 mcm in a vacuum of 0.3 Pa, recovered, and the n investigated by the methods of transmission electron microscopy (TEM) and Auger spectroscopy. The laser pulse energy is approximately 70 J, with the duration of 580 ps and intensity of 440 GV/cm(2). In the recovered samples , the formation of crystalline carbyne is observed with the lattice paramet er a of 0.516 and 0.533 nm. Closely packed carbyne crystals are revealed fo r the first time, which consist of linear chains without kink, as well as c rystals of the characteristic size of similar to 10 mcm, which is an order of magnitude larger than the previously observed sizes. The electron diffra ction data are used to calculate the electron potentials of carbyne crystal s. The calculation results confirm that the carbon chains are packed in a c lose-packed hexagonal structure with minor distinctions for crystals formed in different parts of the sample. A minor amount of ultradisperse diamond is further detected in recovered samples of amorphous carbon.