I am developing a coarse-grained model of RNAs to quantitatively predict the stability of hairpins. For monovalent ions (such as NaCl), the model gives the reliable predictions for the stability of small hairpins as compared with the extensive experimental data. Now, I want to extend the model to predict the stability of RNA hairpins in multivalent ions (e.g., Mg2+) or mixture (e.g., Na+ and Mg2+ ) solution. However, such experimental data I can find is too little to test the model. Who can help me? Thanks very much!