RI−Calc: A user friendly software and web server for refractive index calculation

• Published in: Computer physics communications 2024-05, Vol.298, p.109100, Article 109100
• Main Authors: Benatto, Leandro, Mesquita, Omar, Roman, Lucimara S., Koehler, Marlus, Capaz, Rodrigo B., Candiotto, Graziâni
• Format: Article
• Language: English
• Subjects: Absorption coefficient; Kramers−Kronig; Lorentz oscillator model; Refractive index
• ISSN: 0010-4655; 1879-2944
• DOI: 10.1016/j.cpc.2024.109100

The refractive index of an optical medium is essential for studying a variety of physical phenomena. One useful method for determining the refractive index of scalar materials (i.e., materials which are characterized by a scalar dielectric function) is to employ the Kramers−Kronig (K−K) relations. The K−K method is particularly useful in cases where ellipsometric measurements are unavailable, a situation that frequently occurs in many laboratories. Although some packages can perform this calculation, they usually lack a graphical interface and are complex to implement and use. Those deficiencies inhibit their utilization by a plethora of researchers unfamiliar with programming languages. To address the aforementioned gap, we have developed the Refractive Index Calculator (RI−Calc) program that provides an intuitive and user−friendly interface. The RI−Calc program allows users to input the absorption coefficient spectrum and then easily calculate the complex refractive index and the complex relative permittivity of a broad range of thin films, including of molecules, polymers, blends, and perovskites. The program has been thoroughly tested, taking into account the Lorentz oscillator model and experimental data from a materials' refractive index database, demonstrating consistent outcomes. It is compatible with Windows, Unix, and macOS operating systems. You can download the RI−Calc binaries from our GitHub repository or conveniently access the program through our dedicated web server at nanocalc.org. •Refractive index and relative permittivity determination from the absorption coefficient spectrum.•The method has been validated for molecular acceptors, polymers, blends and perovskites.•Methodology in agreement with experimental data and the Lorentz oscillator model.•Free license code that can be used via a dedicated web server or downloading the binary files.•Intuitive and user−friendly interface.