[QE-users] problems with DFT+U+V (No atom equivalent to r2 error)

[Iurii TIMROV]

Dear Corina,


Please do not forget to indicate your affiliation.


You are trying to model a V-O dimer, right? Note that DFT+U+V was designed for periodic solids. Also note that a virtual 3x3x3 supercell is created in DFT+U+V to find the indices of neighboring atoms to assign the inter-site Hubbard V interaction (please see the discussion on page 11 in this paper: arXiv:2203.15684<https://arxiv.org/abs/2203.15684>).


In order to solve your problem just change the value of the parameter "eps" to e.g. 5.d-5 in PW/src/intersite_V.f90 and then recompile the code. Note that the default value "eps = 5.d-6" works in the majority of cases (at least for periodic solids).


HTH


Greetings,

Iurii


--
Dr. Iurii TIMROV
Senior Research Scientist
Theory and Simulation of Materials (THEOS)
Swiss Federal Institute of Technology Lausanne (EPFL)
CH-1015 Lausanne, Switzerland
+41 21 69 34 881
http://people.epfl.ch/265334
________________________________
From: users <users-bounces at lists.quantum-espresso.org> on behalf of Corina Urdaniz <urdaniz.corina at qns.science>
Sent: Wednesday, June 8, 2022 5:24:24 AM
To: users at lists.quantum-espresso.org
Subject: [QE-users] problems with DFT+U+V (No atom equivalent to r2 error)

Dear All, i'm new in QE, i running  DFT+U+V in simple system (see input below),  and i obtain this error message:

I diff > 0, diff=    1.00000000000000      at1=            1 at2=            1

 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
     Error in routine symonpair (1):
     No atom equivalent to r2
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

 I'm running too in the new development version and I obtain the same error.

&control
calculation = "scf"
prefix = "xxx"
pseudo_dir = "xxxxxx"
outdir = "./tmp"
restart_mode = "from_scratch"
nstep = 500
/
&system
  ibrav=6,
  A=12.375
   C= 29
   nat=2,
   ntyp=2,
   ecutwfc =70,
   ecutrho= 600,
occupations='smearing',
smearing='mv'
degauss=0.005
starting_magnetization(1)=0.7
starting_magnetization(2)=-0.07
vdw_corr = 'grimme-d3'
nspin=2
lda_plus_u = .true.
lda_plus_u_kind = 2
U_projection_type = 'ortho-atomic',
Hubbard_V(1,1,1)=1
Hubbard_V(1,2,2)=2
/
&electrons
electron_maxstep = 500,
conv_thr = 1.0D-8,
mixing_beta = 0.3,
/
&IONS
/
ATOMIC_SPECIES
V   50.9415   v_pbe_v1.4.uspp.F.UPF
O  15.999   O.pbe-n-kjpaw_psl.0.1.UPF
ATOMIC_POSITIONS (angstrom)
V            5.1550456485        5.1550098098       14.1845777826
O            5.1549976674        5.1549967180       12.0833856727
K_POINTS automatic
1 1 1 0 0 0

for the new development i try with this card:
HUBBARD (ortho-atomic)
V V-3d V-3d    1 1 1.2
V V-3d V-4s    1 1 0.5
V V-3d O-2p   1 2  2
V V-4s V-4s    1 1  0.5


the problem was  solved when i changed the coordinates  to something like:

ATOMIC_POSITIONS (angstrom)
V 0.0 0.0 0.0
O 0.0 0.0 2.0



but I get the same error as above if I use the positions from relax.out

Is it a bug, or is it just the question of some parameter tweaking?


TIA!

all the best,

Corina.
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