[CP2K-user] [CP2K:19377] Optimizing with TIP3P a water cluster model

['Vittorio Bariosco' via cp2k]

Dear CP2K users,

I have been through different threads on this forum to understand how to 
optimize a cluster of 600 hundred atoms (see 0_tip3p_geom.xyz) with TIP3P 
model.

1)I firstly tried this input taken from the FIST repository on GitHub here 
<https://github.com/cp2k/cp2k/blob/master/tests/Fist/regtest-4/H2O-1.inp>
(see first_tip3p.inp) but I was always getting this error after the 
Optimization starts:
"WARNING| Particles:     600    598 at distance [au]:     1.82837959 less 
than:      2.00430963; increase EMAX_SPLINE.
GEOMETRY wrong or EMAX_SPLINE too small!"




2)The I moved to the other input reported in the same repository at this 
link 
<https://github.com/cp2k/cp2k/blob/master/tests/Fist/regtest-4/H2O-32_SPME_fp.inp.>
, where more water molecules were included in the initial geometry. In this 
case (see second_tip3p.inp),  the optimization starts but at a certain 
point it crashes again with a similar error: 

"WARNING| Particles:     600    598 at distance [au]:     0.89796367 less 
than:      0.95400000; increase EMAX_SPLINE."

GEOMETRY wrong or EMAX_SPLINE too small! 


At this point I am a little confused on how to proceed. I remembered that 
tip3p is a rigid FF and I started to look for constraining options for 
intramolecular distances and angles. I found in the same input of the above 
the section &CONSTRAINT &G3X3.


3) Thus, I defined the new input using this constrain that could probably 
explains the reason why CP2K was crushing before in this way (see 
third_tip3p.inp). However, also this test was unsuccessful with the 
following error:


"    |  Error in constraints setup!

    |  A constraint has been defined for a molecule type

    |   but the atoms specified in the constraint and the atoms defined for

    |   the molecule DO NOT match!

    |  This could be very probable due to a wrong connectivity, or an error

    |   in the constraint specification in the input file.

    |   Please check it carefully!"


Moreover, I also found in another thread here 
<https://groups.google.com/g/cp2k/c/ld5pmmYUnBk/m/iZte7XZGBwAJ>, that the 
specified constrained keyword works only for MD runs and not for GEO_OPT or 
CELL_OPT. 


At the moment I don't have any clue in how to proceed to obtain a optimized 
geometry with tip3p model. For this reason I would like to ask if anybody 
have ever optimized with tip3p model, or can help me for setting the proper 
input.


Hope to hear from you.


Kindly,


Vittorio




-- 
You received this message because you are subscribed to the Google Groups "cp2k" group.
To unsubscribe from this group and stop receiving emails from it, send an email to cp2k+unsubscribe at googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/cp2k/e32370de-519b-4fd3-9176-438ddf027704n%40googlegroups.com.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.cp2k.org/archives/cp2k-user/attachments/20231017/8663e31b/attachment-0001.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: second_tip3p.inp
Type: chemical/x-gamess-input
Size: 1702 bytes
Desc: not available
URL: <https://lists.cp2k.org/archives/cp2k-user/attachments/20231017/8663e31b/attachment-0003.inp>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 0_tip3p_geom.xyz
Type: chemical/x-xyz
Size: 40531 bytes
Desc: not available
URL: <https://lists.cp2k.org/archives/cp2k-user/attachments/20231017/8663e31b/attachment-0001.xyz>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: third_tip3p.out
Type: application/octet-stream
Size: 30550 bytes
Desc: not available
URL: <https://lists.cp2k.org/archives/cp2k-user/attachments/20231017/8663e31b/attachment-0003.obj>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: first_tip3p.inp
Type: chemical/x-gamess-input
Size: 1732 bytes
Desc: not available
URL: <https://lists.cp2k.org/archives/cp2k-user/attachments/20231017/8663e31b/attachment-0004.inp>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: second_tip3p.out
Type: application/octet-stream
Size: 72236 bytes
Desc: not available
URL: <https://lists.cp2k.org/archives/cp2k-user/attachments/20231017/8663e31b/attachment-0004.obj>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: third_tip3p.inp
Type: chemical/x-gamess-input
Size: 1695 bytes
Desc: not available
URL: <https://lists.cp2k.org/archives/cp2k-user/attachments/20231017/8663e31b/attachment-0005.inp>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: first_tip3p.out
Type: application/octet-stream
Size: 65572 bytes
Desc: not available
URL: <https://lists.cp2k.org/archives/cp2k-user/attachments/20231017/8663e31b/attachment-0005.obj>