[Thermo_pw-forum] The free energy of the adsorbed molecule

[Yun Yang]

I tried again to improve the relax convergence accuracy, for forc_conv_thr=1.0d-05, but there still 3N imaginary frequencies, which I though was unreasonable.

Here are the vibrational frequencies of a carbon monoxide molecule adsorbed over a surface.
     freq (   1-   1) =       -235.7  [cm-1]   --> A               I+R
     freq (   2-   2) =       -199.4  [cm-1]   --> A               I+R
     freq (   3-   3) =       -185.2  [cm-1]   --> A               I+R
     freq (   4-   4) =        -58.0   [cm-1]   --> A               I+R
     freq (   5-   5) =        -49.5   [cm-1]   --> A               I+R
     freq (   6-   6) =        -29.6   [cm-1]   --> A               I+R
     freq (  94-  94) =        68.8   [cm-1]   --> A               I+R
     freq (  95-  95) =        74.5   [cm-1]   --> A               I+R
     freq (  96-  96) =      410.0   [cm-1]   --> A               I+R
     freq (  97-  97) =      433.5   [cm-1]   --> A               I+R
     freq (  98-  98) =      457.0   [cm-1]   --> A               I+R
     freq (  99-  99) =    1993.1   [cm-1]   --> A               I+R
--
Postgraduate Yun Yang
School of Chemical Science and Technology
Yunnan University
2 North Road of Green Lake, Kunming 650091, Yunnan, China
Tel.:+86-871-65033723, Fax: +86-871-65033679, E-mail: yy9702 at mail.ynu.edu.cn
From: Yun Yang<mailto:yy9702 at outlook.com>
Sent: 2021年6月30日 23:27
To: thermo_pw-forum at lists.quantum-espresso.org<mailto:thermo_pw-forum at lists.quantum-espresso.org>
Subject: 回复: The free energy of the adsorbed molecule

Yes, there are several smaller imaginary frequencies. I haven’t seen anyone use thermo_pw to calculate the free energy of electrocatalysis, and I suspect that thermos_pw can’t calculate the energy. I will calculate it again after relax the intermediates, thank you very much!

--
Postgraduate Yun Yang
School of Chemical Science and Technology
Yunnan University
2 North Road of Green Lake, Kunming 650091, Yunnan, China
Tel.:+86-871-65033723, Fax: +86-871-65033679, E-mail: yy9702 at mail.ynu.edu.cn
发件人: Yun Yang<mailto:yy9702 at outlook.com>
发送时间: 2021年6月30日 22:00
收件人: thermo_pw-forum at lists.quantum-espresso.org<mailto:thermo_pw-forum at lists.quantum-espresso.org>
主题: The free energy of the adsorbed molecule

Dear thermo_pw user

I am try to calculate electrocatalytic reduction of carbon dioxide with thermos_pw.1.4.1, but when I calculate the free energy of the adsorbed molecule, the contribution of vibration entropy is nearly 10 times larger than that calculated by other software and the Zero point vibration energy is similar. My calculation flow is first relax the intermediates with high convergence accuracy, than perform thermos_pw.x for calculate the free energy of adsorbed molecules with fixed the slab. My question is does thermos_pw support this and why does the calculation make such a big difference. Here are the ph_control and thermo_control:

&INPUTPH
  tr2_ph=1.0d-16,
  prefix='CoN4-CO',
  fildyn='CoN4-CO.dyn',
  ldisp=.TRUE.,
  trans=.TRUE.,
  nat_todo=2,
  nq1=1,
  nq2=1,
  nq3=1,
/
32 33

&INPUT_THERMO
  what='scf_disp',
  nq1_d=192,
  nq2_d=192,
  nq3_d=192,
  ltherm_dos=.FALSE.,
  ltherm_freq=.TRUE.
/

Thank you very much in advance for your time

Sincerely yours

--
Postgraduate Yun Yang
School of Chemical Science and Technology
Yunnan University
2 North Road of Green Lake, Kunming 650091, Yunnan, China
Tel.:+86-871-65033723, Fax: +86-871-65033679, E-mail: yy9702 at mail.ynu.edu.cn



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