DEW {CHNOSZ} | R Documentation |

## Deep Earth Water (DEW) Model

### Description

Calculate thermodynamic properties of water using the Deep Earth Water (DEW) model.

### Usage

```
calculateDensity(pressure, temperature, error = 0.01)
calculateGibbsOfWater(pressure, temperature)
calculateEpsilon(density, temperature)
calculateQ(density, temperature)
```

### Arguments

`pressure` |
numeric, pressure (bar) |

`temperature` |
numeric, temperature (°C) |

`error` |
numeric, residual error for bisection calculation |

`density` |
numeric, density (g/cm^3) |

### Details

The Deep Earth Water (DEW) model, described by Sverjensky et al., 2014, extends the applicability of the revised HKF equations of state to 60 kbar. This implementation of DEW is based on the VBA macro code in the May, 2017 version of the DEW spreadsheet downloaded from http://www.dewcommunity.org/. The spreadsheet provides multiple options for some calculations; here the default equations for density of water (Zhang and Duan, 2005), dielectric constant (Sverjensky et al., 2014) and Gibbs energy of water (integral of volume, equation created by Brandon Harrison) are used.

Comments in the original code indicate that `calculateGibbsOfWater`

is valid for 100 ≤ *T* ≤ 1000 °C and *P* ≥ 1000 bar.
Likewise, the power function fit of the dielectric constant (epsilon) is valid for 100 ≤ *T* ≤ 1200 °C and *P* ≥ 1000 bar (Sverjensky et al., 2014).

### Value

The calculated values of density, Gibbs energy, and the Q Born coefficient have units of g/cm^3, cal/mol, and bar^-1 (epsilon is dimensionless).

### References

Sverjensky, D. A., Harrison, B. and Azzolini, D. (2014) Water in the deep Earth: The dielectric constant and the solubilities of quartz and corundum to 60 kb and 1,200 °C. *Geochim. Cosmochim. Acta* **129**, 125–145. doi:10.1016/j.gca.2013.12.019

Zhang, Z. and Duan, Z. (2005) Prediction of the *PVT* properties of water over wide range of temperatures and pressures from molecular dynamics simulation. *Phys. Earth Planet. Inter.* **149**, 335–354. doi:10.1016/j.pepi.2004.11.003

### See Also

`water.DEW`

; use `water("DEW")`

to activate these equations for the main functions in CHNOSZ.

### Examples

```
pressure <- c(1000, 60000)
temperature <- c(100, 1000)
calculateGibbsOfWater(pressure, temperature)
(density <- calculateDensity(pressure, temperature))
calculateEpsilon(density, temperature)
calculateQ(density, temperature)
```

*CHNOSZ*version 2.1.0 Index]