Journal of Chemical Physics. Reference A09.12.0028


TITLE: Can gas hydrate structures be described using classical simulations?

All Authors: Maria M. Conde, Carlos Vega, Carl McBride, Eva G. Noya, 
	     Rafael Ramirez y Luis M. Sese

DESCRIPTION:

Results of enthalpy (H) and density (rho) from PI simulations using 
the TIP4PQ/2005 model at different temperatures for the empty hydrates 
(sI, sII and sH) and for a series of solid phases (ice Ih, II, III, V and VI).
At p=1bar, H ~ E (H=U+pV)
The energies at 0K were obtained by using the fit: E=a0+a1*T^2+a2*T^3
The number of molecules used in the simulations for each solid phase
is denoted as N 

water potential: TIP4PQ/2005
simulations path-integral



Phase               T (K)    	H (kcal/mol)     rho (g/cm^3)
_______________________________________________________________
                     250.         -11.214	0.810
	       	     200.	  -11.584	0.815
hydrate sI	     150. 	  -11.916	0.818
(N=368)		     125. 	  -12.039	0.818
		     100.	  -12.132	0.819
		      77. 	  -12.200	0.819
		E(at 0K)=-12.317 kcal/mol
_______________________________________________________________
       		     250.    	  -11.241	0.799	
		     200.    	  -11.610	0.803
hydrate sII	     150.    	  -11.923	0.806
(N=1088)             125.   	  -12.048	0.807
		     100.  	  -12.151	0.807
		      77.     	  -12.221	0.807
                E(at 0K)=-12.334 kcal/mol
_______________________________________________________________
		     250.    	  -11.133	0.781
	             200.    	  -11.505	0.784
hydrate sH 	     150.    	  -11.832	0.787
(N=408)		     125.   	  -11.965	0.788
		     100.   	  -12.064	0.788
		      77.     	  -12.126	0.788
                E(at 0K)=-12.236 kcal/mol
_______________________________________________________________
		     250. 	  -11.372	0.921
		     200. 	  -11.821	0.925
ice Ih		     150. 	  -12.160	0.928
(N=432)		     125.	  -12.292	0.928
		     100.	  -12.401	0.928
		      77. 	  -12.452	0.927
                E(at 0K)=-12.559 kcal/mol
_______________________________________________________________
		     250.   	  -11.343	1.160
	             200.         -11.742	1.172
ice II	             150.         -12.086	1.182
(N=432)              125.         -12.213	1.185
                     100.         -12.350	1.188
                      77.         -12.403	1.190
                E(at 0K)=-12.539 kcal/mol
_______________________________________________________________
		     250.  	  -11.142	1.114	
		     200.   	  -11.538	1.126
ice III 	     150.   	  -11.880	1.134
(N=324)		     125.  	  -12.021	1.139
		     100.  	  -12.120	1.142
		      77.    	  -12.191	1.146
                E(at 0K)=-12.317 kcal/mol
_______________________________________________________________
		     250.    	  -11.066	1.220
		     200.         -11.466	1.233
ice V                150.         -11.805	1.244
(N=504)              125.         -11.932	1.248
                     100.         -12.064	1.251
                      77.         -12.121	1.253
                E(at 0K)=-12.253 kcal/mol
_______________________________________________________________
		     250.  	  -10.861	1.290
		     200.  	  -11.348	1.313
ice VI		     150.  	  -11.696	1.325
(N=360)		     125. 	  -11.821	1.330
		     100.  	  -11.951	1.334
		      77.   	  -12.003	1.336
                E (at 0K)=-12.107 kcal/mol
________________________________________________________________