The environment-dependent interatomic potential (EDIP) potential v000

Yaser Afshar; Luca Ferraro; Chao Jiang; S. J. McSweeney; Joao F. Justo; Martin Z. Bazant; Efthimios Kaxiras; Vasily V Bulatov; Sidney Yip; Nigel Marks

doi:10.25950/a6a67b9f

Jump to: Files | Wiki

EDIP_LAMMPS__MD_783584031339_000

Title A single sentence description.	The environment-dependent interatomic potential (EDIP) potential v000
Description	This model driver provides a C++ implementation of the Environment Dependent Interatomic Potential (EDIP) [1,2] and is based on the source code of the `edip` and `edip/multi` pair styles found in the LAMMPS software package. It additionally features an `edip/c` mode not found in any pair styles in LAMMPS, which is an extension of EDIP to carbon that accounts for pi-bonding effects [2]. The mode of the driver (`edip` for single-species models, `edip/multi` for multispecies models, or `edip/c` for carbon models with pi-bonding effects) is automatically detected based on the input files provided, which must be ASCII text files. For the `edip` and `edip/multi` modes of operation, the driver expects element and parameter files. The element file contains a unique list of chemical elements. In the case of a single species, it automatically chooses the `edip` mode, whereas if multiple species are present, it automatically selects the `edip/multi` mode. However, this driver only expects a parameter file for the `edip/c` mode, since only pure carbon is supported in that case.
Disclaimer A statement of applicability provided by the contributor, informing users of the intended use of this KIM Item.	None
Content Origin	The model driver is implemented based on the `edip` and `edip/multi` pair styles adapted from the LAMMPS software package and `edip/c` pair style for carbon by Nigel Marks and Sam McSweeney and rewritten, amended and updated by Yaser Afshar with performance improvements. LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator https://www.lammps.org

Contributor	Yaser Afshar
Maintainer	Yaser Afshar
Implementer	Yaser Afshar Luca Ferraro Chao Jiang S. J. McSweeney
Developer	Joao F. Justo Martin Z. Bazant Efthimios Kaxiras Vasily V Bulatov Sidney Yip Nigel Marks
Published on KIM	2021
How to Cite	This Model Driver originally published in [1-2] is archived in OpenKIM [3-5]. [1] Justo JF, Bazant MZ, Kaxiras E, Bulatov VV, Yip S. Interatomic potential for silicon defects and disordered phases. Phys Rev B. 1998;58:2539–50. doi:10.1103/PhysRevB.58.2539 — (Primary Source) A primary source is a reference directly related to the item documenting its development, as opposed to other sources that are provided as background information. [2] Marks NA. Generalizing the environment-dependent interaction potential for carbon. Phys Rev B. 2000;63:035401. doi:10.1103/PhysRevB.63.035401 — (Primary Source) A primary source is a reference directly related to the item documenting its development, as opposed to other sources that are provided as background information. [3] Afshar Y, Ferraro L, Jiang C, McSweeney SJ, Justo JF, Bazant MZ, et al. The environment-dependent interatomic potential (EDIP) potential v000. OpenKIM; 2021. doi:10.25950/a6a67b9f [4] Tadmor EB, Elliott RS, Sethna JP, Miller RE, Becker CA. The potential of atomistic simulations and the Knowledgebase of Interatomic Models. JOM. 2011;63(7):17. doi:10.1007/s11837-011-0102-6 [5] Elliott RS, Tadmor EB. Knowledgebase of Interatomic Models (KIM) Application Programming Interface (API). OpenKIM; 2011. doi:10.25950/ff8f563a Click here to download the above citation in BibTeX format.
Funding	Not available

Short KIM ID The unique KIM identifier code.	MD_783584031339_000
Extended KIM ID The long form of the KIM ID including a human readable prefix (100 characters max), two underscores, and the Short KIM ID. Extended KIM IDs can only contain alpha-numeric characters (letters and digits) and underscores and must begin with a letter.	EDIP_LAMMPS__MD_783584031339_000
DOI	10.25950/a6a67b9f https://doi.org/10.25950/a6a67b9f https://commons.datacite.org/doi.org/10.25950/a6a67b9f
KIM Item Type	Model Driver
KIM API Version	2.2
Simulator Potential Compatibility	LAMMPS : edip — full LAMMPS : edip/multi — full

Models using this Model Driver

EDIP_LAMMPS_JiangMorganSzlufarska_2012_SiC__MO_667792548433_000
EDIP_LAMMPS_JustoBazantKaxiras_1998_Si__MO_315965276297_000
EDIP_LAMMPS_LucasBertolusPizzagalli_2009_SiC__MO_634310164305_000
EDIP_LAMMPS_Marks_2000_C__MO_374144505645_000

Download

EDIP_LAMMPS__MD_783584031339_000.txz	Tar+XZ	Linux and OS X archive
EDIP_LAMMPS__MD_783584031339_000.zip	Zip	Windows archive

Wiki

# The Environment-Dependent Interatomic Potential (EDIP)

This directory contains the environment-dependent interatomic potential (EDIP) model driver [[1,2,3,4,5](#references)].

## EDIP model driver

This model driver provides a C++ implementation of the Environment Dependent Interatomic Potential (EDIP) [[1,2,3](#references)] and is based on the source code of the ['edip'](https://docs.lammps.org/pair_edip.html) and ['edip/multi'](https://docs.lammps.org/pair_edip.html) pair styles found in the LAMMPS software package [[4,5](#references)]. It additionally features an `edip/c` mode not found in any pair styles in LAMMPS, which is an extension of EDIP to carbon that accounts for pi-bonding effects [[2,3](#references)].

The three modes of the EDIP driver are,

- [edip](#edip-style)
- [edip/multi](#edipmulti-style)
- [edip/c](#edipc-style)

The mode of the driver (`edip` for single-species models, `edip/multi` for multispecies models, or `edip/c` for carbon models with pi-bonding effects) is automatically detected based on the input files provided, which must be ASCII text files. For the `edip` and `edip/multi` modes of operation, the driver expects an [**element**](#edip-element-file-format) file and a [**parameter**](#edip-parameter-file-format) file. The element file contains a unique list of chemical elements. In the case of a single species, it automatically chooses the `edip` mode, whereas if multiple species are present, it automatically selects the `edip/multi` mode. However, this driver only expects a [**parameter**](#edipc-parameter-file-format) file for the `edip/c` mode, since only pure carbon is supported in that case.

**NOTE:**

We adapted the LAMMPS format from the [LAMMPS documentation](https://docs.lammps.org) as of `July 30, 2021`.

## EDIP style

The current model is an empirical potential popular for modeling silicon materials [[1](#references)]. It consists of two and three-body interactions with theoretically motivated functional forms that capture chemical and physical trends. The two and three-body terms have environment dependence controlled by the atomic coordination Z. The total energy is written as a sum of on-site energies,

$$U_i  = \sum_j U_{2}(r_{ij}, Z_{i}) + \sum_{j < k} U_{3}(r_{ij}, r_{ik}, Z_{i}),$$

The pair potential `U2` is an interaction between atoms `i` and `j` representing pairwise bonds, and `U3` is the interaction between atoms `i`, `j`, and `k` centered at atom `i` representing angular forces.

$$
  \begin{align*}
  &U_{2}(r, Z) = A\left[\left(\frac{B}{r}\right)^{\rho} - e^{-\beta Z^2}\right]exp{\left(\frac{\sigma}{r-a}\right)} \\
  &U_{3}(r_{ij}, r_{ik}, Z_i) = exp{\left(\frac{\gamma}{r_{ij}-a}\right)}exp{\left(\frac{\gamma}{r_{ik}-a}\right)}h(cos\theta_{ijk},Z_i).
  \end{align*}
$$

The two-body term, `U2` includes repulsive and attractive interactions, which go to zero at a distance equals to `a`. The three-body term, `U3` contains radial and angular factors. Both types of interactions depend on the local environment of atom `i` through its effective coordination number, defined by,

$$Z_i = \sum_{j \ne i} f(R_{ij}),$$

where `f` is a cutoff function that measures the contribution of neighbor `j` to the coordination of atom `i` in terms of the separation `r`. The neighbor function is unity for `r` less than `c`, with a gentle drop from `1` to `0` between `c` and `a`, and it is `0` for `r` greater than `a`.

$$
f(r) = \begin{cases}
       1 & \quad r<c \\
       \exp\left(\frac{\alpha}{1-x^{-3}}\right) & \quad c<r<a \\
       0 & \quad r>a
       \end{cases}
$$

All neighbors within the distance `c` to the particle `i` have full contribution, while others between `c` and `a` have a partial contribution to the coordination number `Z`. The angular function,

$$h(l,Z)=\lambda [(1-e^{-Q(Z)(l+\tau(Z))^2}) + \eta Q(Z)(l+\tau(Z))^2],$$

is strongly dependent on the local coordination through two functions,

$$\tau(Z)=u_1 + u_2 (u_3 e^{-u_4 Z} - e^{-2u_4 Z}),$$

and

$$Q(Z)=Q_0 e^{-\mu Z}.$$

These two functions control the equilibrium angle and the strength of the interaction, respectively. The various parameters in the EDIP formulas are listed in a file. The EDIP parameter file. The name usually contains the element name and ends in the `.edip` extension. For example, for a system containing `Si`, the `Si.edip` or `Si.parameter.edip` file contains the specific parameter settings.

### EDIP element file format

The element file contains a unique list of chemical element names separated by spaces:

```bash
  Elem1 Elem2 Elem3 ...
```

For example, for an Si system, the element file may look like this:

```bash
  Si
```

For an Si and C alloy system, the element file may look like this:

```bash
  Si C
```

For an alloy system containing Al, Si, Mg, Cu, and Fe, it could look like this:

```bash
  Al Si Mg Cu Fe
```

### EDIP parameter file format

The EDIP parameter file defines parameters for a triplet of elements. The parameters in a single entry corresponding to the two-body and three-body coefficients in the formula above,

```txt
  element1   element2   element3
  A          B          cutoffA   cutoffC   alpha   beta   eta
  gamma      lambda     mu        rho       sigma   Q0
  u1         u2         u3        u4
```

`element1` is the center atom in a 3-body interaction. The `A`, `B`, `beta`, and `sigma` parameters are used only for two-body interactions. The `eta`, `gamma`, `lambda`, `mu`, `Q0` and all `u1` to `u4` parameters are used for three-body interactions. The `alpha` and `cutoffC` parameters are used for the coordination environment function.

`A` and `lambda` have energy units, while `B`, `cutoffA`, `cutoffC`, `gamma`, and `sigma` have distance units and the rest of the parameters are pure numbers [[1](#references)].

### EDIP style example

As an example, a KIM Portable Model (PM) for pure Si systems that uses this model driver with the edip style contains the following two input files,

```bash
  elems.edip
  Si.edip
```

where `elems.edip` element file contains,

```bash
# list of elements
# Elem1
  Si
```

and the `Si.edip` parameter file contains,

```bash
# DATE: 2011-09-15 CONTRIBUTOR: Unknown CITATION: Justo, Bazant, Kaxiras, Bulatov and Yip, Phys Rev B, 58, 2539 (1998)

# EDIP parameters for various elements and mixtures
# multiple entries can be added to this file, LAMMPS reads the ones it needs
# these entries are in LAMMPS "metal" units

# format of a single entry (one or more lines)
#
#   element 1, element 2, element 3,
#     A   B   cutoffA   cutoffC   alpha   beta   eta
#     gamma   lambda    mu   rho   sigma   Q0
#     u1   u2   u3   u4
#
# units for each parameter:
#     A , lambda are in eV
#     B, cutoffA, cutoffC, gamma, sigma are in Angstrom
#     alpha, beta, eta, mu, rho, Q0, u1-u4 are pure numbers

# Here are the original parameters in metal units, for silicon from:
# J. F. Justo, M. Z. Bazant, E. Kaxiras, V. V. Bulatov, S. Yip
#       Phys. Rev. B 58, 2539 (1998)
#

Si Si Si 7.9821730 1.5075463 3.1213820 2.5609104 3.1083847 0.0070975 0.2523244
         1.1247945 1.4533108 0.6966326 1.2085196 0.5774108 312.1341346
         -0.165799 32.557 0.286198 0.66
```

## EDIP/MULTI style

This style supports multi-element systems, where the element file contains a unique list of elements. In addition, its parameter file must contain the number of unique elements to the power of 3 entries. For example, for a two-element system, the file must contain 8 entries and for a three-element system, the file must contain 27 entries.

### EDIP/MULTI style example

As an example, a KIM Portable Model (PM) for modeling silicon carbide is a two-element system. It contains the following two input files,

```bash
  elems.edip
  SiC.edip
```

where `elems.edip` element file contains,

```bash
# list of elements
# Elem1 Elem2
  Si    C
```

and the `SiC.edip` parameter file contains,

```bash
# DATE: 2017-05-16 CONTRIBUTOR: Laurent Pizzagalli CITATION: G. Lucas, M. Bertolus, and L. Pizzagalli, J. Phys. : Condens. Matter 22, 035802 (2010)
#
#   element 1, element 2, element 3,
#     A   B   cutoffA   cutoffC   alpha   beta   eta
#     gamma   lambda    mu   rho   sigma   Q0
#     u1   u2   u3   u4
#
# units for each parameter:
#     A , lambda are in eV
#     B, cutoffA, cutoffC, gamma, sigma are in Angstrom
#     alpha, beta, eta, mu, rho, Q0, u1-u4 are pure numbers
#

Si Si Si 5.488043 1.446435 2.941586 2.540193 3.066580 0.008593 0.589390
         1.135256 2.417497 0.629131 1.343679 0.298443 208.924548
         -0.165799 32.557 0.286198 0.66

C C C    10.222599 0.959814 2.212263 1.741598 1.962090 0.025661 0.275605
         1.084183 3.633621 0.594236 2.827634 0.536561 289.305617
         -0.165799 32.557 0.286198 0.66

C Si Si  7.535967 1.177019 2.534972 1.973974 2.507738 0.015347 0.432497
         1.191567 3.025559 0.611684 2.061835 0.423863 249.115082
         -0.165799 32.557000 0.286198 0.660000

Si C C   7.535967 1.177019 2.534972 1.973974 2.507738 0.015347 0.432497
         1.191567 3.025559 0.611684 2.061835 0.423863 249.115082
         -0.165799 32.557000 0.286198 0.660000

Si Si C  5.488043 1.446435 2.941586 2.540193 3.066580 0.008593 0.510944
         1.135256 2.721528 0.620407 1.343679 0.298443 229.019815
         -0.165799 32.557000 0.286198 0.660000

Si C Si  7.535967 1.177019 2.534972 1.973974 2.507738 0.015347 0.510944
         1.191567 2.721528 0.620407 2.061835 0.423863 229.019815
         -0.165799 32.557000 0.286198 0.660000

C C Si   10.222599 0.959814 2.212263 1.741598 1.962090 0.025661 0.354051
         1.084183 3.329590 0.602960 2.827634 0.536561 269.210350
         -0.165799 32.557000 0.286198 0.660000

C Si C   7.535967 1.177019 2.534972 1.973974 2.507738 0.015347 0.354051
         1.191567 3.329590 0.602960 2.061835 0.423863 269.210350
         -0.165799 32.557000 0.286198 0.660000
```

The file must contain 8 entries for `SiSiSi`, `SiSiC`, `SiCSi`, `SiCC`, `CSiSi`, `CSiC`, `CCSi`, `CCC`, that specify EDIP parameters for all permutations of the two elements interacting in three-body configurations.

## EDIP/C style

The `edip/c` [[2](#references)] style is a transferable empirical potential developed for carbon by extending the environment-dependent interaction potential proposed for silicon [[1](#references)]. This implementation extends EDIP [[1](#references)] to describe carbon, and in doing so, addresses the most significant weakness of silicon EDIP, namely, the absence of $$\pi$$-bonding effects. With this improvement important phenomena such as dihedral rotation penalties and $$\pi$$-repulsion are described.

The functional form of carbon EDIP consists of three components,

- Two-body pair energy,
- Three-body angular penalty,
- Generalized coordination.

Following silicon EDIP [[1](#references)], the two and three-body terms have environment dependence controlled by the atomic coordination Z. Within this framework, the total energy is written as a sum of on-site energies.

$$U_i=\sum_j U_{2}(r_{ij}, Z_{i})+\sum_{j<k}U_{3}(r_{ij},r_{ik},\theta_{jik},Z_{i}),$$

`U2` resembles the SW potential in being short-ranged, decaying to zero at a distance set by the denominator in the exponential term.

$$U_{2}(r,Z)=\epsilon\left[\left(\frac{B}{r}\right)^4-e^{-\beta Z^2}\right]\exp{\left(\frac{\sigma}{r-a-a'Z}\right)}.$$

The $$-\beta Z^2$$ describes the bond order. The three-body term follows silicon EDIP [[1](#references)] in using SW-like radial and angular terms with environmental dependence, having the form,

$$U_{3}(r_{ij},r_{ik},\theta,Z)=\lambda(Z)g(r_{ij},Z)g(r_{ik},Z)h(\theta,Z).$$

The components of `U3` are defined by,

$$
  \begin{align*}
  &\lambda(Z)=\lambda_0\exp[-\lambda'(Z-Z_0)^2],\\
  &g(r,Z)=\exp[\gamma/(r-a-a'Z)],\\
  &h(\theta,Z)=1-\exp\left\{-q[\cos\theta+\tau(Z)]^2\right\}.
  \end{align*}
$$

$$\tau(Z)$$ describes the variation in ideal bonding angle and is defined by, $$\tau(Z)=1-\frac{Z}{12}\tanh[t_1(Z-t_2)].$$ The spherical coordination contribution $$z_i$$ is
determined by the sum $$z_i=\sum{f(R_{ij})},$$ where $$f(R)$$ is a three-parameter function defined by,

$$
f(r) = \begin{cases}
       1 & \quad r<f_{low} \\
       \exp\left(\frac{\alpha}{1-x^{-3}}\right) & \quad f_{low}<r<f_{high} \\
       0 & \quad r>f_{high}
       \end{cases}
$$

The generalized coordination $$Z_i$$ augments $$z_i,$$

$$
  Z_i=z_i+\pi_3(z_i)X_i^{dih}+\pi_3(z_i)X_i^{rep3}+\pi_2(z_i)X_i^{rep2}.
$$

$$\pi_2$$ and $$\pi_3$$ are switching functions identifying 2-coordinated and 3-coordinated atoms and $$X_i$$ describes dihedral rotation, $$\pi$$-repulsion at a threefold site, and $$\pi$$-repulsion at a twofold site. Vector products capture the appropriate symmetries via the functions,

$$
  \begin{align*}
  &X_i^{dih}=Z_{dih}\sum \pi_3(z_j)(\mathbf{\hat{R}_{jm}.\hat{R}_{ik}\times\hat{R}_{il}})^2C^{dih}_{ijklm},\\
  &X_i^{rep3}=Z_{rep}\sum \pi(z_j)(\mathbf{\hat{R}_{ij}.\hat{R}_{ik}\times\hat{R}_{il}})^2C^{rep3}_{ijkl},\\
  &X_i^{rep2}=Z_{rep}\sum \pi(z_j)[1-(\mathbf{\hat{R}_{ij}.\hat{R}_{ik}})^2]C^{rep2}_{ijk}.
  \end{align*}
$$

where `jkl` are neighbors of `i`, and `m` is a neighbor of `j`, and $$\pi(z)$$ selects for twofold or threefold sites. The distance-based cutoff functions `C` are,

$$
  \begin{align*}
  &C^{dih}_{ijklm}=p(R_{ij})p(R_{ik})p(R_{il})p(R_{jm}),\\
  &C^{rep3}_{ijkl}=(R_{ij}-c_0)^2[1-p(R_{ij})]p(R_{ik})p(R_{il}),\\
  &C^{rep2}_{ijk}=(R_{ij}-c_0)^2[1-p(R_{ij})]p(R_{ik}).
  \end{align*}
$$

with the function `p(r)` equivalent to `f(r)` except for different endpoints. The various parameters in the `EDIP/C` formulas are listed in a parameter file. Usually, it is called the `C.edip` parameter file.

**NOTE:**

To accurately model close-ranged interactions between atoms, the pair potential within the EDIP for carbon (EDIP/C) formalism is smoothly switched to the Ziegler-Biersacke-Littermark (ZBL) pair potential at small separations. However, due to the environmental dependence, this transition is less straightforward than pair potentials, where one can use interpolation functions to connect the potentials. Here [[3](#references)], the approach is to use two Fermi-type scaling functions,

$$
  \begin{align*}
  f_{zbl}(r)=\left[1+\exp{\left(\frac{r-r_c+\delta}{s}\right)}\right]^{-1},\\
  f_{edip}(r)=1-\left[1+\exp{\left(\frac{r-r_c-\delta}{s}\right)}\right]^{-1},
  \end{align*}
$$

where $$r_c$$ is the cutoff distance, $$\delta$$ is the shift, and $$s$$ is the skin (controls the sharpness of the transition).

### EDIP/C parameter file format

The `EDIP/C` parameter file defines parameters coefficients,

```txt
  eps   BB       beta         sigma  a      aprime
  Z0    lambda0  lambdaprime  gamma  q
  flow  fhigh    alpha        plow   phigh  Zdih  Zrep  c0
  zbl   cutoff   skin         shift
```

The `eps`, `BB`, `beta`, `sigma`, `a`, and `aprime` parameters are used for two-body interactions. The `Z0`, `lambda0`, `lambdaprime`, `gamma`, and `q` parameters are used for three-body interactions. The `flow`, `fhigh`, `alpha`, `plow`, `phigh`, `Zdih`, and `Zrep` parameters are used for the coordination environment function. The `zbl` parameter indicates whether the pair potential within the EDIP formalism is smoothly switched to the ZBL pair potential at small separations. Due to environmental dependence, this transition is not straightforward. The approach is to use two Fermi-type scaling functions which are defined using three parameters `cutoff`, `skin`, and `shift`.

`eps`, `lambda0`, `Zdih`, `Zrep` parameters have `energy units`, and `sigma`, `a`, `aprime`, `gamma`, `flow`, `fhigh`, `plow`, `phigh`, `c0`, `cutoff`, `skin`, and `shift` have `distance units`. The `BB` parameter has the power of four `distance unit`. And the rest of the parameters are pure numbers.

**NOTE:**

Setting the `zbl` parameter to `1` indicates using ZBL pair potential and setting it to `0` indicates not using it. If `zbl` parameter is set to `0` any other parameter after that is optional and is ignored.

### EDIP/C style example

As an example, a KIM Portable Model (PM) for modeling carbon contains the following parameter file,

```bash
  C.edip
```

where the `C.edip` parameter file contains,

```bash
# DATE: 2021-06-06         Reference: Marks, N.A., Phys. Rev.B, 63(3):035401, Dec 2000.

# format of a single entry (one or more lines)
#
#     eps   BB       beta         sigma  a      aprime
#     Z0    lambda0  lambdaprime  gamma  q
#     flow  fhigh    alpha        plow   phigh  Zdih  Zrep  c0
#     zbl   cutoff   skin         shift
#
# if zbl is 0, then \c cutoff, \c skin, \c shift are not necessary.
#
# units for each parameters:
#
#     eps, lambda0, Zdih, Zrep -> are in eV
#     sigma, a, aprime, gamma, flow, fhigh, plow, phigh, c0 -> are in Angstrom
#     cutoff, skin, shift -> are in Angstrom
#     BB -> is in Angstrom^4
#     beta, Z0, lambdaprime, q, alpha, -> are pure numbers
#     zbl -> is 0 or 1
#

20.0853862863495  0.827599951322299  0.0490161172713279  1.25714643580808  1.89225338775144  0.169794491000172
3.615             19.86394896867     0.30                1.35419222406125  3.5
1.547             2.270              1.544               1.48              2.000             0.30               0.06  3.2
0
```

## References

[1]  Justo, Jo\~ao F., and Bazant, Martin Z. and Kaxiras, Efthimios and Bulatov, V.V. and Yip, Sidney, "Interatomic potential for silicon defects and disordered phases," Phys. Rev.B, 58(5):2539--2550, Aug 1998.

[2]  Marks, N.A., "Generalizing the environment-dependent interaction potential for carbon," Phys. Rev.B, 63(3):035401, Dec 2000.

[3]  Christie, H.J. and Robinson, M. and Roach, D.L. and Ross, D.K. and Suarez-Martinez, I. and Marks, N.A., "Simulating radiation damage cascades in graphite," carbon, 81:105--114, 2015.

[4] [https://www.lammps.org](https://www.lammps.org)

[5] [https://docs.lammps.org/pair_edip.html](https://docs.lammps.org/pair_edip.html)

Wiki Contributors

2021-08-20T08:17:41.760056	yafshar
2021-08-18T15:15:54.698222	yafshar
2021-08-18T13:28:08.790999	yafshar
2021-08-18T05:33:44.683095	yafshar
2021-08-18T05:31:43.610748	yafshar
2021-08-18T05:29:33.391935	yafshar
2021-08-17T15:44:10.901717	yafshar
2021-08-17T13:01:03.077372	yafshar