CP dynamics requires the existence of a gap in the electronic spectrum.
you can force cp.x to minimize the electronic state by using "cg" as
electron_dynamics method. I would use pw.x to perform BOMD but if you
are more familiar with cp.x you can try that.
stefano
On 27/08/22 15:47, Jayraj Anadani wrote:
Hello sir,
I have one more question regarding this : can I perform the cpmd
simulation method using cp.x in quantum espresso to simulate the
metallic glass system ? I did this cpmd but I couldn't control the
kinetic energy of the electrons because my system is amorphorse
metallic and according to CP user guide the cpmd is not
performing well with amorphous metallic systems. or is BOMD using
pwscf by doing the reduce-T option is good for studying metallic glass ?
kindly suggest a feasible method to do DFT study of metallic glass
alloys using quantum espresso package.
thank you
regards
jayraj anadani
On Fri, Aug 26, 2022 at 10:04 PM Jayraj Anadani
<[email protected]> wrote:
I appreciate your help
Thank you very much sir.
On Fri, 26 Aug, 2022, 7:16 pm Stefano de Gironcoli,
<[email protected]> wrote:
I would take out small clusters from your 10000 cells
(possibly saturate with H atoms if you cut covalent bonds),
not relax (with the exception of relaxing the extra H atoms
you added to saturate), compute atomic PDOS of the central
atom(s) and verify that for increasing number of atoms in the
clusters these quantities stabilize and converge.
if a significant size dependence results you may want to play
with the environ feature (http://www.quantum-environ.org/) to
minimize boundary effects
stefano
On 26/08/22 15:01, Jayraj Anadani wrote:
I have one amorphorse metallic system of 10000 atoms in which
several clusters are in it. I want to calculate atomic
bonding and electronic interaction through finding DOS/PDOS
and Charge analysis of a small cluster part of a large
amorphorse metallic system.
My cluster size is upto 13 to 25 atoms which is part of large
md simulation.
So can i have to do relaxation or i can directly do scf
calculation with restricted parameter ?
Thank you
On Fri, 26 Aug, 2022, 6:04 pm Stefano de Gironcoli,
<[email protected]> wrote:
I dont think that a 10-20 atom cluster configuration
extracted from a 10000 condensed phase has anything to do
with the same system at 300 K.
possibly some electronic properties of the central
molecule may be similar to the corresponding properties
in the condensed phase but no guarantee.
if you relax or perform md for the cluster you loose your
(tiny) connection with the original cell.
I fail to understand what is your problem and what you
would like to compute/understand
stefano
On 26/08/22 13:52, Jayraj Anadani wrote:
Thank you sir, for your reply
but I have one particular molecular system of 10-20
atoms which I am getting from a simulation of a large
atom (around 10000 atoms) at a 300K temperature from a
molecular dynamic simulation (LAMMPS). and I also did
optimization of that MD structure which is
amorphous metallic glass. Now,
Can I do dft study of a small part of a single molecule
of a large MD simulation(~10000 atoms) ?
till now i did below things but i am bit confused which
way is best way to study DFT . i also dis AIMD/CPMD but
for metallic glass CPMD doesn't work good with PAW PP.
so,
1. Can I do direct SCF calculation(without relax) by
giving a condition of *forc_conv_thr* and
*tot_conv_thr* with creating a vacuum(for a non-periodic
system) of around 15 Angstrom to converge properly. *OR*
2. I should do the RELAX calculation with vacuum and
then go to the *scf* calculation to find the total
energy and then *nscf*.
***questions:
1. what if I relax a system and position is changed a
bit(which is obvious) to minimize the total energy but
that energy is at zero kelvin dft calculation and I want
to study the system at 300K. So how can small parts of a
structure reflect large MD simulation structural properties?
Thank you
regards
jayraj anadani
Ph.D. Research scholar Department of physics
sardar patel university
india
On Fri, Aug 26, 2022 at 5:00 PM Stefano de Gironcoli
<[email protected]> wrote:
Dear JAYRAJ ANADANI,
calculation="scf" corresponds to a minimization
of the total energy
at fixed atomic positions. you chose where to put
the ions. the code
does its best to return the corresponding energy.
calculaiton="relax" corresponds to a series of scf
calculations,
followed by forces evaluation and geometry update to
minimize the energy
of the system. The code does its best to converge to
a minimum (non
necessarily the global minimum) in the GS potential
energy surface.
there is no temperature in any of these calculations.
if you want to simulate the system at finite
(classical) temperature
for the atoms you should perform MD simlations
stefano
On 26/08/22 05:02, Jayraj Anadani wrote:
> Dear QE
> I put H2O molecular atoms small far
apart from each
> other within large supercell so that the periodic
image of the H2O do
> not interact with each other and run a scf
calculation my convergence
> done successfully with good amount of accuracy
upto 10^-9. But it is
> not reflecting original H2O molecule at 300
Kelvin...but when i
> relaxing these atoms and then did scf calculation
they are reflecting
> H2O at 300k by observing bond angel and length..
how ? And my question is
> 1) scf is also doing calculation using iteration
method algorithm by
> using electronic densities at ground state so why
they converge when
> two hydrogen atoms and one oxygen atom are not at
appropriate
> distance.still scf converge how ?
> 2) also by doing relax calculation all of sudden
two hydrogen and one
> oxygen come closer and they formed a bond and bond
angel which is
> reflect 300k H2O molecule structure. So how two
hydrogen and one
> oxygen atoms knows during relaxation that i have
to make structure at
> a room temperature?
>
>
> Thank you
> Regards
>
> JAYRAJ ANADANI
> Ph.D Research scholar
> Department of physics
> Sardar Patel University
> Anand,Gujarat,
> India
>
> _______________________________________________
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_______________________________________________
The Quantum ESPRESSO community stands by the Ukrainian
people and expresses its concerns about the devastating
effects that the Russian military offensive has on their
country and on the free and peaceful scientific,
cultural,
and economic cooperation amongst peoples
_______________________________________________
Quantum ESPRESSO is supported by MaX
(www.max-centre.eu <http://www.max-centre.eu>)
users mailing list [email protected]
https://lists.quantum-espresso.org/mailman/listinfo/users
_______________________________________________
The Quantum ESPRESSO community stands by the Ukrainian
people and expresses its concerns about the devastating
effects that the Russian military offensive has on their
country and on the free and peaceful scientific, cultural,
and economic cooperation amongst peoples
_______________________________________________
Quantum ESPRESSO is supported by MaX (www.max-centre.eu
<http://www.max-centre.eu>)
users mailing [email protected]
https://lists.quantum-espresso.org/mailman/listinfo/users
_______________________________________________
The Quantum ESPRESSO community stands by the Ukrainian
people and expresses its concerns about the devastating
effects that the Russian military offensive has on their
country and on the free and peaceful scientific, cultural,
and economic cooperation amongst peoples
_______________________________________________
Quantum ESPRESSO is supported by MaX (www.max-centre.eu
<http://www.max-centre.eu>)
users mailing list [email protected]
https://lists.quantum-espresso.org/mailman/listinfo/users
_______________________________________________
The Quantum ESPRESSO community stands by the Ukrainian
people and expresses its concerns about the devastating
effects that the Russian military offensive has on their
country and on the free and peaceful scientific, cultural,
and economic cooperation amongst peoples
_______________________________________________
Quantum ESPRESSO is supported by MaX (www.max-centre.eu
<http://www.max-centre.eu>)
users mailing [email protected]
https://lists.quantum-espresso.org/mailman/listinfo/users
_______________________________________________
The Quantum ESPRESSO community stands by the Ukrainian
people and expresses its concerns about the devastating
effects that the Russian military offensive has on their
country and on the free and peaceful scientific, cultural,
and economic cooperation amongst peoples
_______________________________________________
Quantum ESPRESSO is supported by MaX (www.max-centre.eu
<http://www.max-centre.eu>)
users mailing list [email protected]
https://lists.quantum-espresso.org/mailman/listinfo/users
_______________________________________________
The Quantum ESPRESSO community stands by the Ukrainian
people and expresses its concerns about the devastating
effects that the Russian military offensive has on their
country and on the free and peaceful scientific, cultural,
and economic cooperation amongst peoples
_______________________________________________
Quantum ESPRESSO is supported by MaX (www.max-centre.eu)
users mailing [email protected]
https://lists.quantum-espresso.org/mailman/listinfo/users
_______________________________________________
The Quantum ESPRESSO community stands by the Ukrainian
people and expresses its concerns about the devastating
effects that the Russian military offensive has on their
country and on the free and peaceful scientific, cultural,
and economic cooperation amongst peoples
_______________________________________________
Quantum ESPRESSO is supported by MaX (www.max-centre.eu)
users mailing list [email protected]
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