[gmx-users] About negative values deuterium order parameters

[Poncho Arvayo Zatarain]

Some days ago i send a quetion about negative values of deuterium order parameters in a 25% DPPC 75% DPPE+ nesthesic membrane. Thomas Piggot repond to me about the Scd que be negative too, specially for DPPC and DPPE. Now i send my obatained values for Scd. It is correct to have negative values? SN-1 and SN-3 correspond to DPPC and SN-2 and SN-4 correspond to DPPE. I watch the gro file in vmd and certainly look inclinable for the tails. All my other systems don´t have negative values like this one.

Carbon  DPPC64+DPPE192+AN-SN1   DPPC64+DPPE192+AN-SN2   DPPC64+DPPE192+AN-SN3   DPPC64+DPPE192+AN-SN4
1       -0.207868       0.156621        -0.122543       0.202863
2       -0.199115       0.0507337       0.075788        0.0911758
3       -0.129733       0.0328502       0.0638192       0.0722099
4       0.159087        -0.0813808      0.0432806       0.0571403
5       -0.0940551      -0.0807225      -0.0842683      0.189616
6       -0.199373       -0.0259852      -0.0721477      0.167733
7       0.122858        -0.0486781      0.00461267      0.132131
8       0.135019        -0.0244167      -0.0931847      0.132473
9       0.134224        0.0127981       0.0474575       0.143573
10      0.135023        0.0502274       0.0901911       0.132179
11      0.128295        -0.0841136      0.0882197       0.0943604
12      0.125227        0.0756042       0.0349276       0.12459
13      0.115938        0.220139        -0.0766258      0.0861008