# Data for: Fast methods of Debye-Hückel limiting slopes calculation and low-temperature extrapolation based on IAPWS equation of state of water

## Description

This dataset consists of two parts: 1) Tabulated values for the Debye-Hückel limiting slopes (Aphi, AH/(RT), AC/R, AV, AE, AK) obtained by means of IAPWS equations of state for water. They are stored in .csv files. 2) Software (IAPWS-DH library) that allows to calculate the Debye-Hückel limiting slopes using IAPWS95, IAPWS-IF97 equations. It also supports some other popular equations set (Archer-1990, Bradley&Pitzer-1979). This computer program is written in ANSI C and is cross-platform; at least MS Windows, GNU/Linux and DOS platforms are supported. The tables were calculated next way: * At T>=273.15: direct usage of IAPWS95 equation. * At T<273.15: usage of high-accurate approximation of IAPWS95 equation by means of 2D orthogonal polynomials (to overcome numerical differentiation accuracy problems). This approach allows to obtain the Debye-Hückel coefficients values for a very low temperature down to about 150 K that can be useful in thermodynamic modelling of very concentrated aqueous solutions using such models as Pitzer, eNRTL or eUNIQUAC models.

## Files

## Steps to reproduce

The *.csv tables with the Debye-Hückel coefficients values can be reproduced by the IAPWS-DH library that is supplied as the source code. To use it you should have at least one of the next three software products: * C compiler. It is required to build C part of the IAPWS-DH library including bindings to Python and MATLAB. You can use cmake, GNU make or nmake to build it. It's recommended to use GCC or MS Visual C++ to compile the project. * Python 3.x with installed NumPy and matplotlib: either for work with "pure" Python implementation of IAPWS equations or with C extensions. * MATLAB or GNU/Octave: either for work with "pure" MATLAB implementation of IAPWS equations or with C extensions (MEX-files). It's recommended to use Doxygen to make C source code documentation.