Nanoscale physics

Discrete stages of phase transitions in nanostructures and extremal properties of substances
Kornienko N. E. 1, Korniienko A. N. , Kirichenko A.N.2

1 Taras Shevchenko National University of Kyiv,, Volodymyrska str., 64/3,
 Kyiv-01601, Ukraine.
E-mail: email.of. corresponding_nikkorn@mail.univ.kiev.ua
2 Technological Institute for Superhard and Novel Carbon Materials,
  Tsentralnaya str., 7a, 142190, Moscow, Troitsk, Russia.
        
The further development of quantum physics and material science is largely determined by the understanding of specific mechanisms of structural transformations of matter, including phase transitions (PT). We have established that ice pre-melting occurs in discrete stages (DS) at temperatures Тi =-30, -19, -11, -7 and -40С with the formation of nanofilms of quasivectors with thickness d = 0,6-10 nm [1]. It is essential that the sum of the partial heats Qi at the DS for d> 2 nm is equal to the specific heat of melting of bulk ice. Studies of DS of PT in detonation nanodiamonds (ND) of size ~5 nm using vibrational spectroscopy during thermal annealing (900-20000С, 10-4 torr) were carried out. Raman (514.5 nm) and IR spectra were obtained at the PT of ND to the onion-shaped carbon in a wide temperature range T. The dependences on T of the parameters D and G of the ND bands and their graphite-like shells, as well as the bands D(k) and G(k’), related to the boundaries of the Brillouin zones, are numerically studied. Two DS PT were detected in the 940-12000С and 1500-20000С intervals, where the maxima of the intensities Imax(Т), the frequencies ν(Т) and the half-width δν(Т) of the vibrational bands are reached. The extreme properties of substances at DS PT are manifested in the sharp increase in the changes in the electronic polarizabilities, in the increase in the dipole vibration for the D(k) 1060-1100 cm-1  band in the IR spectrum, in the anomalous anharmonic frequency shifts Δν=ν(2D)-2ν(D)>0 and the broadening of the width of the phonon band ND Δνф=ν(D)-ν(D(k)), which is due to the enhancement of chemical bonds and the appearance of new electron states. For DS pre-melting of ice, the density of nano-water increases to 1,2-1,3 g/cm3 and the viscosity increases. The discrete nonlinear-quantum nature of the phase transition and strong vibrational-electronic interactions are discussed.

1.	Kornienko M.E., Sheiko N.L., Kornienko O.M., Nikolaenko T.Yu. Discrete properties of quasiliquid water film in the ice premelting range//
 Ukr. J. Phys.-2013.-58. N 2.- Р.151-162.