[gmx-users] how to describe spring between core and shell

[sangyongliang99 at mails.tsinghua.edu.cn]

Dear Erik and David:
I am very much thankfull for your kind help before!
But I have another question which is about how to describe spring const of core
and shell in shell model.My model is  a shell connecting to a core, not to a dummy
particle as in sw.itp, so should I describe the spring using
[position_restraints]?

 
I also have some questions about the position_restraints in sw.itp as follows:

[ position_restraints ]
; See notes above.
; i	funct	kx	ky	kz	rOH	rHH	rOD
#ifdef ANISOTROPIC
1	2 	608069	563101	586116	0.09572	0.15139 0.0137408
#else
1	2 	585318 	585318 	585318 	0.09572 0.15139 0.0137408
#endif

Where is the atom 1 restrained? What does funct 2 mean?