[Quantum Espresso] Water molecule

Reference: https://www.youtube.com/watch?v=qth17pYTnw4&list=PLGntAYRT8AVmQMyurFoncyOdHljqeGU_R&index=5

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1. Purpose of calculation 

Calculation of the bond length and bond angle of H20 molecule

2. Code

1) Input file: H2O.in

&control
    calculation = 'relax'
    prefix = 'h2o'
    pseudo_dir = '/opt/q-e-qe-6.7.0/SSSP_precision_pseudos/'
    etot_conv_thr = 1.0e-5
    forc_conv_thr = 1.0e-4
/
&system
    ibrav = 1, celldm(1) = 10,
    nat = 3, ntyp = 2,
    ecutwfc = 25
/
&electrons
    conv_thr = 1.0e-8
/
&ions
    ion_dynamics ='bfgs'
/
ATOMIC_SPECIES
 H  1.00784 H_ONCV_PBE-1.0.oncvpsp.upf
 O 15.999 O.pbe-n-kjpaw_psl.0.1.UPF
ATOMIC_POSITIONS (angstrom)
 O 0.00 0.00 0.00
 H -1.00 0.01 0.02
 H 1.00 0.01 0.03
K_POINTS (automatic)
 1 1 1 0 0 0

 

3. Results

Fig.1 Left: the initial state. Right: the final state  

 

	Reference	Results from Xcrysden	Error (%)
The bond Length	0.9584 Å	0.9994 Å	4.27
The bond angle	104.45 deg	101.112 deg	3.19