Add CITATION.cff for GBasis journal reference

CITATION.cff

@@ -0,0 +1,48 @@
+cff-version: 1.2.0
+message: "If you use GBasis in your research, please cite the following paper."
+title: "GBasis"
+type: software
+url: "https://github.com/theochem/gbasis"
+license: "BSD-3-Clause"
+preferred-citation:
+  type: article
+  title: "GBasis: A Python Library for Evaluating Functions, Functionals, and Integrals Expressed with Gaussian Basis Functions."
+  authors:
+    - family-names: Kim
+      given-names: Taejin D.
+    - family-names: Pujal
+      given-names: Leila
+    - family-names: Richer
+      given-names: Michelle
+    - family-names: van Zyl
+      given-names: Max
+    - family-names: Martínez-González
+      given-names: Marco
+    - family-names: Tehrani
+      given-names: Amir
+    - family-names: Chuiko
+      given-names: Vladislav
+    - family-names: Sánchez-Díaz
+      given-names: Gabriel
+    - family-names: Sanchez
+      given-names: William
+    - family-names: Adams
+      given-names: William
+    - family-names: Huang
+      given-names: X.
+    - family-names: Kelly
+      given-names: Brian D.
+    - family-names: Vöhringer-Martinez
+      given-names: Esteban
+    - family-names: Verstraelen
+      given-names: Toon
+    - family-names: Heidar-Zadeh
+      given-names: Farnaz
+    - family-names: Ayers
+      given-names: Paul W.
+  journal: "The Journal of Chemical Physics"
+  volume: 161
+  issue: 4
+  pages: 042503
+  year: 2024
+  doi: "10.1063/5.0216776"

website/intro.md

@@ -1,14 +1,15 @@
 <!-- #region -->
 # Welcome to GBasis's Documentation!
+## Citation
+
+If you use **GBasis** in your research, please cite:
+
+> **GBasis: A Python Library for Evaluating Functions, Functionals, and Integrals Expressed with Gaussian Basis Functions.**  
+> Tae Won David Kim, Leila Pujal, Maximilian van Zyl, Alireza Tehrani, Michelle Richer, Gabriela Sánchez-Díaz, Xiaotian Derrick Yang, Valerii Chuiko, Raimundo Hernández-Esparza, William Adams, Xiaomin Huang, Braden D. Kelly, Matthew Chan, Esteban Vöhringer-Martinez, Toon Verstraelen, Farnaz Heidar-Zadeh, and Paul W. Ayers.  
+> *J. Chem. Phys. 161, 042503 (2024).*  
+> https://doi.org/10.1063/5.0216776
 
-[Gbasis](https://github.com/theochem/gbasis/) is a free, open-source, and cross-platform Python library designed to help you effortlessly work with Gaussian-type orbitals. Please use the following citation in any publication using Gbasis library:
 
-**"GBasis: A Python Library for Evaluating Functions, Functionals, and
-Integrals Expressed with Gaussian Basis Functions"**,
-Taewon David Kim, Leila Pujal, Maximilian van Zyl, Alireza Tehrani, Michelle Richer, Gabriela
-Sánchez-Díaz, Xiaotian Derrick Yang, Valerii Chuiko, Raymundo Hernández-Esparza, William Adams,
-Xiaomin Huang, Braden D. Kelly, Matthew Chan, Esteban Vöhringer-Martinez, Toon Verstraelen, Farnaz
-Heidar-Zadeh, and Paul W. Ayers
 
 The GBasis source code is hosted on [GitHub](https://github.com/theochem/gbasis/) and is released under the [GNU LESSER GENERAL PUBLIC LICENSE](https://github.com/theochem/gbasis/blob/master/LICENSE). We welcome any contributions to the GBasis library in accordance with our [Code of Conduct](https://github.com/theochem/gbasis/blob/master/CODE_OF_CONDUCT.md); please see our [Contributing Guidelines](https://github.com/theochem/gbasis/blob/master/CONTRIBUTING.md). Please report any issues you encounter while using GBasis library on [GitHub Issues](https://github.com/theochem/gbasis/issues). For further information and inquiries please contact us at qcdevs@gmail.com.