# [Pw_forum] Cell parameters representation for cubic fcc(111) Iridium structure

Venkataramana Imandi venkataramana.imandi at gmail.com
Sat Sep 26 07:38:09 CEST 2015

``` Dear  Arles V. Gil Rebaza,

What is the significance of cos60 and sin60. I don't know much.

Venkat

PhD student

IIT Bombay

Mumbai

Dear Venkataramana, if you have a FCC(111) surface, probabily you should
have these lattice vectors (is a option representation)

a            0          0
b*cos60  b*sin60 0
0            0          c+h

where a, b, and c are the distance that you are reporting, and "h" is the
vacuum to simulate a surface.

Best.

Arles V. Gil Rebaza
IFLP-Argentina

On Fri, Sep 25, 2015 at 9:46 PM, Venkataramana Imandi <
venkataramana.imandi at gmail.com> wrote:

> Dear all,
>
> I generated cubic fcc(111) in the form of 3x2x2 type structure (6 layers
> and each layer has 12 atoms) with Iridium (lattice constant:3.839
> angstroms).
> In the generated coordinates file, crystal axes are 8.14374880,
> 9.40359112, 13.29868610 (generated coordinate are attached). Can i represent
> CELL_PARAMETERS angstrom in addition to ibrav=0 in the system namelist as
> shown below (for whole Iridium structure).
> 8.14374880  0.00000000    0.000000000
> 0.00000000  9.40359112    0.000000000
> 0.00000000  0.00000000    13.29868610
>
> Is the above representation correct (maintains cubic fcc), if not, please
> suggest me how to represent CELL_PARAMETERS for whole Iridium structure.
> I am new user and please suggest me correct way of doing calculations.
>
> Again, I want to keep manually methane molecule on the top of Iridium (on
> the top of z-axis, above 5 angstroms from the top atom in the z-axis), then
> the resultant whole structure maintain fcc cubic. Please give some
> suggestions. I am new to quantum espresso calculations.
>
>       72      72      72      72
>      8.14374880     9.40359112    13.29868610     0.00000000
> 0.00000000     0.00000000  MD time =   0.000E+00 ps
> Ir           6.78645733          5.48542817          6.64934305
> Ir           5.42916587          7.83632593          6.64934305
> Ir           5.42916587          4.70179556          4.43289536
> Ir           6.78645733          7.05269336          4.43289536
> Ir           5.42916587          6.26906075          2.21644768
> Ir           6.78645733          8.61995854          2.21644768
> Ir           4.07187440          5.48542817          6.64934305
> Ir           2.71458293          7.83632593          6.64934305
> Ir           2.71458293          4.70179556          4.43289536
> Ir           4.07187440          7.05269336          4.43289536
> Ir           2.71458293          6.26906075          2.21644768
> Ir           4.07187440          8.61995854          2.21644768
> Ir           1.35729146          5.48542817          6.64934305
> Ir           0.00000000          7.83632593          6.64934305
> Ir           0.00000000          4.70179556          4.43289536
> Ir           1.35729146          7.05269336          4.43289536
> Ir           0.00000000          6.26906075          2.21644768
> Ir           1.35729146          8.61995854          2.21644768
> Ir           6.78645733          0.78363261          6.64934305
> Ir           5.42916587          3.13453037          6.64934305
> Ir           5.42916587          0.00000000          4.43289536
> Ir           6.78645733          2.35089780          4.43289536
> Ir           5.42916587          1.56726519          2.21644768
> Ir           6.78645733          3.91816298          2.21644768
> Ir           4.07187440          0.78363261          6.64934305
> Ir           2.71458293          3.13453037          6.64934305
> Ir           2.71458293          0.00000000          4.43289536
> Ir           4.07187440          2.35089780          4.43289536
> Ir           2.71458293          1.56726519          2.21644768
> Ir           4.07187440          3.91816298          2.21644768
> Ir           1.35729146          0.78363261          6.64934305
> Ir           0.00000000          3.13453037          6.64934305
> Ir           0.00000000          0.00000000          4.43289536
> Ir           1.35729146          2.35089780          4.43289536
> Ir           0.00000000          1.56726519          2.21644768
> Ir           1.35729146          3.91816298          2.21644768
> Ir           6.78645733          5.48542817          0.00000000
> Ir           5.42916587          7.83632593          0.00000000
> Ir           5.42916587          4.70179556         -2.21644769
> Ir           6.78645733          7.05269336         -2.21644769
> Ir           5.42916587          6.26906075         -4.43289537
> Ir           6.78645733          8.61995854         -4.43289537
> Ir           4.07187440          5.48542817          0.00000000
> Ir           2.71458293          7.83632593          0.00000000
> Ir           2.71458293          4.70179556         -2.21644769
> Ir           4.07187440          7.05269336         -2.21644769
> Ir           2.71458293          6.26906075         -4.43289537
> Ir           4.07187440          8.61995854         -4.43289537
> Ir           1.35729146          5.48542817          0.00000000
> Ir           0.00000000          7.83632593          0.00000000
> Ir           0.00000000          4.70179556         -2.21644769
> Ir           1.35729146          7.05269336         -2.21644769
> Ir           0.00000000          6.26906075         -4.43289537
> Ir           1.35729146          8.61995854         -4.43289537
> Ir           6.78645733          0.78363261          0.00000000
> Ir           5.42916587          3.13453037          0.00000000
> Ir           5.42916587          0.00000000         -2.21644769
> Ir           6.78645733          2.35089780         -2.21644769
> Ir           5.42916587          1.56726519         -4.43289537
> Ir           6.78645733          3.91816298         -4.43289537
> Ir           4.07187440          0.78363261          0.00000000
> Ir           2.71458293          3.13453037          0.00000000
> Ir           2.71458293          0.00000000         -2.21644769
> Ir           4.07187440          2.35089780         -2.21644769
> Ir           2.71458293          1.56726519         -4.43289537
> Ir           4.07187440          3.91816298         -4.43289537
> Ir           1.35729146          0.78363261          0.00000000
> Ir           0.00000000          3.13453037          0.00000000
> Ir           0.00000000          0.00000000         -2.21644769
> Ir           1.35729146          2.35089780         -2.21644769
> Ir           0.00000000          1.56726519         -4.43289537
> Ir           1.35729146          3.91816298         -4.43289537
>
> Venkat
> PhD research scholar
> IIT Bombay
> Mumbai
>
>

--
venkataramana
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