Re: [ESPResSo-users] fully attractive potential

[Dudo]

Yes, it is, at least for my phantom particles.

At the moment it looks it's working with these settings:

set ljsigma 1.0                           

set ljepsilon 10.0                        

set ljrcut 5.0                               

set ljcshift 0.0                             

set ljroff [expr -1.0*$ljsigma * pow (2., 1./6.)]                                   

set ljrcap 0.0

set ljrmin 0.0

So, I must have been doing wrong something else :-)

Thanks for help,

Dusan

On Wed, Jul 27, 2016 at 2:41 PM, Peter Košovan <address@hidden> wrote:

We've had a similar discussion a few years back and concluded that Espresso does not (and should not) prevent you from using such values because it is the user's responsibility to have the physics right. Negative time step is possible but it does not mean you can simulate the past. If you use purely attractive potentials, then the ground state is all particles in one spot = a black hole. Is that what you are aiming for?

Greetings,

peter

On Wed, Jul 27, 2016 at 1:53 PM, Georg Rempfer <address@hidden> wrote:

I see nothing wrong with either of the two. If you try it please let us know whether the interface allows you to use these parameters.

On Wed, Jul 27, 2016 at 1:24 PM, Dudo <address@hidden> wrote:

Hi,

is it a proper way to set the r_off parameter in the Lennard-Jones interaction 

to an negative value in order to get a fully attractive potential?

Or, similarly, could I set the epsilon in gaussian interaction to a negative value,

or negative values are somehow ignored?

Thank you

Dusan

--

_____________________

Faculté de biologie et de médecine

Center for Integrative Genomics

GENOPODE UNIL-SORGE

Université de Lausanne

CH1015 Lausanne, Suisse [+]

RG: https://www.researchgate.net/profile/Dusan_Racko

Scholar: https://goo.gl/oRVrGV

Polymer Institute of the Slovak Academy of Sciences

Dubravska cesta 3

845 41 Bratislava, Slovak Republic [‡]

tel: +421 2 3229 4321

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Dr. Peter Košovan

Department of Physical and Macromolecular Chemistry

Faculty of Science, Charles University in Prague, Czech Republic

Katedra fyzikální a makromolekulární chemie

Přírodovědecká fakulta Univerzity Karlovy v Praze

www.natur.cuni.cz/chemistry/fyzchem/
Tel. +420221951290

Fax +420224919752

--

_____________________

Faculté de biologie et de médecine

Center for Integrative Genomics

GENOPODE UNIL-SORGE

Université de Lausanne

CH1015 Lausanne, Suisse [+]

RG: https://www.researchgate.net/profile/Dusan_Racko

Scholar: https://goo.gl/oRVrGV

Polymer Institute of the Slovak Academy of Sciences

Dubravska cesta 3

845 41 Bratislava, Slovak Republic [‡]

tel: +421 2 3229 4321