Re: Expectation values other than energy

[Lucas Wagner]

(I'm repeating this for the list, as it incorrectly identified your email as spam)

Hi Nagat,

I don't think there are examples, but it's simple. If you want to calculate the dipole moment, just put 

average { dipole } 

into your VMC or DMC section. 

Other possible quantities are available here:

http://www.qwalk.org/docs/docs/PropertiesDoc.html

Best,

Lucas

On Fri, May 23, 2014 at 8:49 AM, Nagat Elkahwagy <nagat.e...@gmail.com> wrote:

Hi Lucas

Please, If there are any examples to begin calculating expectation values other than energy ( bond length- dipole moment) like the example folder or the tutorial?

 

Many thanks

 

Regards

Nagat

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[Marc Segovia]

Good Morning

 About dipole estimation, which is the reference to vectors, shown in qwalk output ? more heavy atom, center of mass, geometrical center ?

Thanking in advance your help

 Best Regards

 Marc

 Dr. Marc Segovia

CCBG-DETEMA

Facultad de Química

Universidad de la Republica

11800 Montevideo

Uruguay

[Lucas Wagner]

Hi Marc,

The DIPOLE operator calculates the average of \sum q_i r_i, where the sum goes over both nuclei and electrons. If your molecule is neutral, then the result will be independent of reference. If it's charged, then there will be an additional component related to the center of charge.

Lucas

[Marc Segovia]

Dear Lucas

Thank you by your quick answer

 Nice weekend.

 Marc

[Marc Segovia]

Good Afternoon

 When I ask to estimate dipole during DMC, no results appears after gosling, however when done using RMC, they appear.

 But if I look inside dmc.log, dipole average is shown in each block

 There is an special flag to ask gosling to shown it, when using in DMC ?

 Thanking your help in advance

 Best Regards

 Marc

[Lucas Wagner]

Dear Marc,

No, it should work. Gosling doesn't distinguish between RMC and DMC. Could you give a minimal working example of your problem, and also share which version of QWalk you're using?

Lucas

[Marc Segovia]

Dear Lucas

Thank you by your help, 

Below are dmc and rmc input files

method { DMC timestep .01

 average { dipole }

 nconfig 20

 nstep 10000

 timestep .001

 readconfing mol.vmc.config

 storeconfig mol.dmc.config

include nak.sys

trialfunc { include mol.opt.wfout }

method { REPTATION

 nblock 200

 nstep 1000

 timestep 0.01

 readconfig mol.vmc.config

 storeconfig mol.rmc.config.2

 length 400

 average { dipole }

}

include mol.sys

trialfunc { include mol.opt.wfout }

version 0.96.5

Best Regards

Marc

[Lucas Wagner]

Hi Marc,

0.96.5 is very old; I would suggest using the github version. Check the tutorials on github for using new (a few years old now!) syntax. Your input file for DMC doesn't seem to be correct; you have timestep twice and are missing close brackets. The way that you have the storeconfig/readconfig set up is quite error prone, and I don't recommend setting those manually.

Actually, there is kind of strange behavior with the average variables. If the first block in the log file does *not* have the average { } section in it, then gosling will not display it. So if you ran DMC without the average {} section, and then ran it with the average { } section, then you would get that behavior.

Best,

Lucas

[Marc Segovia]

Hi Lucas

 Thank you by your quick answer and hints.

 I will install new version and solve syntax errors.

 Best Regards

 Marc