Relation between Rotational and Translational Dynamic Heterogeneities in Water.pdfVIP

Relation between Rotational and Translational Dynamic Heterogeneities in Water Marco G. Mazza,1 Nicolas Giovambattista,2, 1 Francis W. Starr,3 and H. Eugene Stanley1 5 0 1 Center for Polymer Studies and Department of Physics, 0 2 Boston University, Boston, Massachusetts 02215, USA l u 2 J Department of Chemical Engineering, Princeton University, 8 Princeton, New Jersey 08544-5263, USA 2 ] 3Department of Physics, Wesleyan University, t f o Middletown, Connecticut 06459, USA s t. (Dated: February 2, 2008) a m Abstract - d n We use molecular dynamics simulations to probe the rotational dynamics of the SPC/E model of o c water for a range of temperatures down to 200 K, 13 K above to the mode coupling temperature. [ 1 We find that rotational dynamics is spatially heterogeneous, i.e., there are clusters of molecules v 0 that rotate significantly more than the average for a given time interval, and we study the size and 6 6 the temporal behavior of these clusters. We find that the position of a rotational heterogeneity 7 0 is strongly correlated with the position of a translational heterogeneity, and that the fraction of 5 0 molecules belonging to both kinds of heterogeneities increases with decreasing temperature. We / t a further find that although the two types of heterogeneities are not identical, they are related to m - the same physical picture. d n o c PACS numbers: 61.20.Ja, 61.20.Gy : v i X r a