Previous Thread
Next Thread
Print Thread
#22783 11/12/09 01:51 PM
Joined: Nov 2005
Posts: 10
M
Forum Member
OP Offline
Forum Member
M
Joined: Nov 2005
Posts: 10
I notice that in Charmm parameter files some atoms have two sets of vdw parameters - one for the 'normal' vdw interaction and the other for 1-4 vdw interaction. For example:

C 0.000000 -0.110000 2.000000 ! ALLOW PEP POL ARO
! NMA pure solvent, adm jr., 3/3/93

and
CT1 0.000000 -0.020000 2.275000 0.000000 -0.010000 1.900000 ! ALLOW ALI
! isobutane pure solvent properties, adm jr, 2/3/92

My question is this: if an atom does not contain the second set of parameters (such as C as shown above), does Charmm still include the 1-4 interactions for an atom pair that contain atom C?

Joined: Sep 2003
Posts: 4,840
Likes: 3
Forum Member
Offline
Forum Member
Joined: Sep 2003
Posts: 4,840
Likes: 3
yes


Lennart Nilsson
Karolinska Institutet
Stockholm, Sweden
Joined: Nov 2005
Posts: 10
M
Forum Member
OP Offline
Forum Member
M
Joined: Nov 2005
Posts: 10
If so, which set of parameters is it using? Is it the first set?

Joined: Sep 2003
Posts: 4,840
Likes: 3
Forum Member
Offline
Forum Member
Joined: Sep 2003
Posts: 4,840
Likes: 3
If the second set is missing the values from the first set are used as 1-4 parameters for that atomtype.


Lennart Nilsson
Karolinska Institutet
Stockholm, Sweden

Moderated by  alex, lennart, rmv 

Link Copied to Clipboard
Powered by UBB.threads™ PHP Forum Software 7.7.5
(Release build 20201027)
Responsive Width:

PHP: 7.3.31-1~deb10u1 Page Time: 0.010s Queries: 22 (0.006s) Memory: 0.7404 MB (Peak: 0.7887 MB) Data Comp: Off Server Time: 2022-08-16 11:54:51 UTC
Valid HTML 5 and Valid CSS