********************* The 4th., Lab Seminar **********************

Date: Thu, June 19, 2003  PM 4:00-

Place: No.616 Seminar room
　　　　　　 Graduate School of Information Science

Speaker: Yoshiyuki Koyano 

Title: Surface melting of (0001) face of TIP4P ice
        (G. J. Kroes, Surf. Sci. 275, 365 (1992).)

Abstract:  The onset of surface melting of the basal plane (0001)
        face of TIP4P ice is studied in the temperature range
        T = 190-250 K using the molecular dynamics (MD) method.
        The disordering of the surface seen in the calculations
        can be explained in terms of the disruption of the hydrogen
        bonding network at the surface. At T = 210 K and lower the
        surface remains solid-like, as evidenced by non-zero order
        parameters and no calculable self-diffusion, although the
        reorientational correlation time (ca. 100 ps) is closer to
        that of the liquid than that of bulk ice. On the other hand,
        at T = 230 K (-43°C) and higher the surface is liquid-like,
        as shown by low order parameters and a high translational
        and rotational mobility of the molecules. At all temperatures,
        there is an orientational preference for the water molecule
        pointing its protons down.  The polarisation of the surface
        increases with increasing temperature.

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