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Slow glassy dynamics and fragile-to-strong crossover in supercooled aqueous magnesium perchlorate solutions: The effect of Martian solutes

P. La Francesca, L. Lupi, and P. Gallo*

  • *Contact author: paola.gallo@uniroma3.it
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Phys. Rev. E 114, 035416 – Published 15 September, 2026

DOI: https://doi.org/10.1103/hpn9-7sls

Abstract

The dynamical behavior of water in magnesium perchlorate aqueous solutions is investigated through molecular dynamics simulations using the TIP4P/2005 water model and the recently extended Madrid-2019 force field. This study is motivated by the recent radar detection of liquid water underneath the Martian South Pole. We explore the supercooled regime for salt concentrations up to 24.4 wt %. In the region of mild supercooling we analyze the water oxygen self-intermediate scattering functions. Our results show that the relaxation dynamics of water is well described by the mode coupling structural relaxation in this region. Upon further cooling, a fragile-to-strong crossover is observed for all investigated concentrations. Below the crossover, activated processes maintain the ergodicity. Notably, the addition of magnesium perchlorate induces a downward shift in both the mode coupling temperature and the fragile-to-strong crossover temperature. This combined effect extends the range of existence of the supercooled liquid regime to lower temperatures compared to bulk water. These findings support the hypothesis that perchlorate aqueous solutions can persist in a thermodynamically metastable liquid state at the low-temperature conditions of the Martian subsurface.

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References (87)

  1. P. Gallo, K. Amann-Winkel, C. A. Angell, M. A. Anisimov, F. Caupin, C. Chakravarty, E. Lascaris, T. Loerting, A. Z. Panagiotopoulos, J. Russo, J. A. Sellberg, H. E. Stanley, H. Tanaka, C. Vega, L. Xu, and L. G. M. Pettersson, Water: A tale of two liquids, Chem. Rev. 116, 7463 (2016).
  2. P. Gallo and H. E. Stanley, Supercooled water reveals its secrets, Science 358, 1543 (2017).
  3. P. G. Debenedetti, Supercooled and glassy water, J. Phys.: Condens. Matter 15, R1669 (2003).
  4. C. A. Angell, Supercooled water, Annu. Rev. Phys. Chem. 34, 593 (1983).
  5. P. Debenedetti, Metastable Liquids: Concepts and Principles, Physical Chemistry: Science and Engineering (Princeton University Press, Princeton, NJ, 1996).
  6. P. Gallo and M. Rovere, Physics of Liquid Matter, Soft and Biological Matter (Springer International Publishing, Berlin, 2021).
  7. R. Orosei, S. E. Lauro, E. Pettinelli, A. Cicchetti, M. Coradini, B. Cosciotti, F. D. Paolo, E. Flamini, E. Mattei, M. Pajola, F. Soldovieri, M. Cartacci, F. Cassenti, A. Frigeri, S. Giuppi, R. Martufi, A. Masdea, G. Mitri, C. Nenna, R. Noschese, et al., Radar evidence of subglacial liquid water on Mars, Science 361, 490 (2018).
  8. S. E. Lauro, E. Pettinelli, G. Caprarelli, L. Guallini, A. P. Rossi, E. Mattei, B. Cosciotti, A. Cicchetti, F. Soldovieri, M. Cartacci, F. Di Paolo, R. Noschese, and R. Orosei, Multiple subglacial water bodies below the south pole of Mars unveiled by new MARSIS data, Nat. Astron. 5, 63 (2021).
  9. R. J. Speedy, P. G. Debenedetti, R. S. Smith, C. Huang, and B. D. Kay, The evaporation rate, free energy, and entropy of amorphous water at 150 K, J. Chem. Phys. 105, 240 (1996).
  10. O. Mishima and H. E. Stanley, The relationship between liquid, supercooled and glassy water, Nature (London) 396, 329 (1998).
  11. K. H. Kim, A. Späh, H. Pathak, F. Perakis, D. Mariedahl, K. Amann-Winkel, J. A. Sellberg, J. H. Lee, S. Kim, J. Park, et al., Maxima in the thermodynamic response and correlation functions of deeply supercooled water, Science 358, 1589 (2017).
  12. A. Nilsson, Origin of the anomalous properties in supercooled water based on experimental probing inside “no-man's land”, J. Non-Cryst. Solids: X 14, 100095 (2022).
  13. M. Seidl, A. Fayter, J. N. Stern, G. Zifferer, and T. Loerting, Shrinking water's no man's land by lifting its low-temperature boundary, Phys. Rev. B 91, 144201 (2015).
  14. W. Götze, Complex Dynamics of Glass-Forming Liquids: A Mode-Coupling Theory (Oxford University Press, Oxford, UK, 2008).
  15. P. Gallo, F. Sciortino, P. Tartaglia, and S.-H. Chen, Slow dynamics of water molecules in supercooled states, Phys. Rev. Lett. 76, 2730 (1996).
  16. F. Sciortino, P. Gallo, P. Tartaglia, and S.-H. Chen, Supercooled water and the kinetic glass transition, Phys. Rev. E 54, 6331 (1996).
  17. R. Torre, P. Bartolini, and R. Righini, Structural relaxation in supercooled water by time-resolved spectroscopy, Nature (London) 428, 296 (2004).
  18. M. De Marzio, G. Camisasca, M. Rovere, and P. Gallo, Mode coupling theory and fragile to strong transition in supercooled TIP4P/2005 water, J. Chem. Phys. 144, 074503 (2016).
  19. M. De Marzio, G. Camisasca, M. Rovere, and P. Gallo, Microscopic origin of the fragile to strong crossover in supercooled water: The role of activated processes, J. Chem. Phys. 146, 084502 (2017).
  20. L. Lupi, B. Vázquez Ramírez, and P. Gallo, Dynamical crossover and its connection to the Widom line in supercooled TIP4P/ice water, J. Chem. Phys. 155, 054502 (2021).
  21. P. Gallo, M. Rovere, and S.-H. Chen, Water confined in MCM-41: A mode coupling theory analysis, J. Phys.: Condens. Matter 24, 064109 (2012).
  22. L. Liu, S.-H. Chen, A. Faraone, C.-W. Yen, and C.-Y. Mou, Pressure dependence of fragile-to-strong transition and a possible second critical point in supercooled confined water, Phys. Rev. Lett. 95, 117802 (2005).
  23. F. Mallamace, M. Broccio, C. Corsaro, A. Faraone, U. Wanderlingh, L. Liu, C.-Y. Mou, and S.-H. Chen, The fragile-to-strong dynamic crossover transition in confined water: Nuclear magnetic resonance results, J. Chem. Phys. 124, 161102 (2006).
  24. P. Gallo, M. Rovere, and E. Spohr, Supercooled confined water and the mode coupling crossover temperature, Phys. Rev. Lett. 85, 4317 (2000).
  25. P. Gallo, D. Corradini, and M. Rovere, Fragile to strong crossover at the Widom line in supercooled aqueous solutions of NaCl, J. Chem. Phys. 139, 204503 (2013).
  26. G. Camisasca, M. De Marzio, M. Rovere, and P. Gallo, High density liquid structure enhancement in glass forming aqueous solution of LiCl, J. Chem. Phys. 148, 222829 (2018).
  27. S.-H. Chen, L. Liu, E. Fratini, P. Baglioni, A. Faraone, and E. Mamontov, Observation of fragile-to-strong dynamic crossover in protein hydration water, Proc. Natl. Acad. Sci. USA 103, 9012 (2006).
  28. M. Lagi, X. Chu, C. Kim, F. Mallamace, P. Baglioni, and S.-H. Chen, The low-temperature dynamic crossover phenomenon in protein hydration water: Simulations vs experiments, J. Phys. Chem. B 112, 1571 (2008).
  29. G. Camisasca, M. De Marzio, D. Corradini, and P. Gallo, Two structural relaxations in protein hydration water and their dynamic crossovers, J. Chem. Phys. 145, 044503 (2016).
  30. A. Iorio, G. Camisasca, M. Rovere, and P. Gallo, Characterization of hydration water in supercooled water-trehalose solutions: The role of the hydrogen bonds network, J. Chem. Phys. 151, 044507 (2019).
  31. L. Lupi and P. Gallo, Glassy dynamics of water in TIP4P/ice aqueous solutions of trehalose in comparison with the bulk phase, J. Chem. Phys. 159, 154504 (2023).
  32. A. Iorio, L. Perin, and P. Gallo, Structure and slow dynamics of protein hydration water with cryopreserving DMSO and trehalose upon cooling, J. Chem. Phys. 160, 244502 (2024).
  33. L. Lupi and P. Gallo, Mode coupling behavior and fragile to strong transition of trehalose in a binary mixture with water upon supercooling, J. Chem. Phys. 160, 244501 (2024).
  34. L. Perin and P. Gallo, The effect of the cryoprotectant dimethyl sulfoxide on water upon supercooling: A molecular dynamics study, J. Chem. Phys. 163, 214501 (2025).
  35. P. Gallo and M. Rovere, Mode coupling and fragile to strong transition in supercooled TIP4P water, J. Chem. Phys. 137, 164503 (2012).
  36. M. De Marzio, G. Camisasca, M. Rovere, and P. Gallo, Fragile to strong crossover and Widom line in supercooled water: A comparative study, Front. Phys. 13, 136103 (2018).
  37. F. W. Starr, S. Harrington, F. Sciortino, and H. E. Stanley, Slow dynamics of water under pressure, Phys. Rev. Lett. 82, 3629 (1999).
  38. A. Faraone, L. Liu, C.-Y. Mou, C.-W. Yen, and S.-H. Chen, Fragile-to-strong liquid transition in deeply supercooled confined water, J. Chem. Phys. 121, 10843 (2004).
  39. P. Gallo, M. Rovere, and S.-H. Chen, Dynamic crossover in supercooled confined water: Understanding bulk properties through confinement, J. Phys. Chem. Lett. 1, 729 (2010).
  40. R. Tyburski, M. Shin, S. You, K. Nam, M. Soldemo, A. Girelli, M. Bin, S. Lee, I. Andronis, Y. Han, S. Jeong, R. A. Oggenfuss, R. Mankowsky, D. Babich, X. Liu, S. Zerdane, T. Katayama, H. Lemke, F. Perakis, A. Nilsson, et al., Observation of a dynamic transition in bulk supercooled water, Nat. Phys. 22, 21 (2026).
  41. P. H. Poole, F. Sciortino, U. Essmann, and H. E. Stanley, Phase behaviour of metastable water, Nature (London) 360, 324 (1992).
  42. J. C. Palmer, F. Martelli, Y. Liu, R. Car, A. Z. Panagiotopoulos, and P. G. Debenedetti, Metastable liquid–liquid transition in a molecular model of water, Nature (London) 510, 385 (2014).
  43. Y. Liu, J. C. Palmer, A. Z. Panagiotopoulos, and P. G. Debenedetti, Liquid-liquid transition in ST2 water, J. Chem. Phys. 137, 214505 (2012).
  44. Y. Liu, A. Z. Panagiotopoulos, and P. G. Debenedetti, Low-temperature fluid-phase behavior of ST2 water, J. Chem. Phys. 131, 104508 (2009).
  45. F. Sciortino, I. Saika-Voivod, and P. H. Poole, Study of the ST2 model of water close to the liquid–liquid critical point, Phys. Chem. Chem. Phys. 13, 19759 (2011).
  46. T. A. Kesselring, E. Lascaris, G. Franzese, S. V. Buldyrev, H. J. Herrmann, and H. E. Stanley, Finite-size scaling investigation of the liquid-liquid critical point in ST2 water and its stability with respect to crystallization, J. Chem. Phys. 138, 244506 (2013).
  47. F. Smallenburg and F. Sciortino, Tuning the liquid-liquid transition by modulating the hydrogen-bond angular flexibility in a model for water, Phys. Rev. Lett. 115, 015701 (2015).
  48. P. Gallo and F. Sciortino, Ising universality class for the liquid-liquid critical point of a one component fluid: A finite-size scaling test, Phys. Rev. Lett. 109, 177801 (2012).
  49. P. G. Debenedetti, F. Sciortino, and G. H. Zerze, Second critical point in two realistic models of water, Science 369, 289 (2020).
  50. J. Weis, F. Sciortino, A. Z. Panagiotopoulos, and P. G. Debenedetti, Liquid–liquid criticality in the wail water model, J. Chem. Phys. 157, 024502 (2022).
  51. Y. Li, J. Li, and F. Wang, Liquid–liquid transition in supercooled water suggested by microsecond simulations, Proc. Natl. Acad. Sci. USA 110, 12209 (2013).
  52. R. Weldon and F. Wang, Water potential from adaptive force matching for ice and liquid with revised dispersion predicts supercooled liquid anomalies in good agreement with two independent experimental fits, J. Phys. Chem. B 128, 3398 (2024).
  53. F. Sciortino, Y. Zhai, S. L. Bore, and F. Paesani, Constraints on the location of the liquid–liquid critical point in water, Nat. Phys. 21, 480 (2025).
  54. O. Mishima and H. E. Stanley, Decompression-induced melting of ice IV and the liquid–liquid transition in water, Nature (London) 392, 164 (1998).
  55. K. Winkel, E. Mayer, and T. Loerting, Equilibrated high-density amorphous ice and its first-order transition to the low-density form, J. Phys. Chem. B 115, 14141 (2011).
  56. S. Woutersen, B. Ensing, M. Hilbers, Z. Zhao, and C. A. Angell, A liquid-liquid transition in supercooled aqueous solution related to the HDA-LDA transition, Science 359, 1127 (2018).
  57. K. H. Kim, K. Amann-Winkel, N. Giovambattista, A. Späh, F. Perakis, H. Pathak, M. L. Parada, C. Yang, D. Mariedahl, T. Eklund, T. J. Lane, S. You, S. Jeong, M. Weston, J. H. Lee, I. Eom, M. Kim, J. Park, S. H. Chun, P. H. Poole, et al., Experimental observation of the liquid-liquid transition in bulk supercooled water under pressure, Science 370, 978 (2020).
  58. S. You et al., Experimental evidence of a liquid-liquid critical point in supercooled water, Science 391, 1387 (2026).
  59. D. G. Archer and R. W. Carter, Thermodynamic properties of the NaCl + H2O system. 4. Heat capacities of H2O and NaCl(aq) in cold-stable and supercooled states, J. Phys. Chem. B 104, 8563 (2000).
  60. D. Corradini, M. Rovere, and P. Gallo, A route to explain water anomalies from results on an aqueous solution of salt, J. Chem. Phys. 132, 134508 (2010).
  61. D. Corradini, Z. Su, H. E. Stanley, and P. Gallo, A molecular dynamics study of the equation of state and the structure of supercooled aqueous solutions of methanol, J. Chem. Phys. 137, 184503 (2012).
  62. L.-A. Näslund, D. C. Edwards, P. Wernet, U. Bergmann, H. Ogasawara, L. G. M. Pettersson, S. Myneni, and A. Nilsson, X-ray absorption spectroscopy study of the hydrogen bond network in the bulk water of aqueous solutions, J. Phys. Chem. A 109, 5995 (2005).
  63. D. Corradini, M. Rovere, and P. Gallo, Structural properties of high and low density water in a supercooled aqueous solution of salt, J. Phys. Chem. B 115, 1461 (2011).
  64. D. Corradini and P. Gallo, Liquid–liquid coexistence in NaCl aqueous solutions: A simulation study of concentration effects, J. Phys. Chem. B 115, 14161 (2011).
  65. I. Waluyo, D. Nordlund, U. Bergmann, D. Schlesinger, L. G. M. Pettersson, and A. Nilsson, A different view of structure-making and structure-breaking in alkali halide aqueous solutions through x-ray absorption spectroscopy, J. Chem. Phys. 140, 244506 (2014).
  66. L. Perin and P. Gallo, Phase diagram of aqueous solutions of LiCl: A study of concentration effects on the anomalies of water, J. Phys. Chem. B 127, 4613 (2023).
  67. L. Perin and P. Gallo, Thermodynamics, phase diagram, structure and anomalies of supercooled aqueous solutions of trehalose: A molecular dynamics study, J. Mol. Liq. 414, 126089 (2024).
  68. C. Calvagna, A. Lapini, A. Taschin, S. Fanetti, M. Pagliai, P. Bartolini, R. Bini, R. Righini, and R. Torre, Modification of local and collective dynamics of water in perchlorate solution, induced by pressure and concentration, J. Mol. Liq. 337, 116273 (2021).
  69. P. La Francesca and P. Gallo, Supercooled solutions of sodium perchlorate in TIP4P/2005 water: The effect of Martian solutes on thermodynamics and structure, J. Chem. Phys. 159, 124501 (2023).
  70. P. La Francesca and P. Gallo, Phase diagram and structure of TIP4P/2005 water and magnesium perchlorate: A molecular dynamic study of Martian aqueous solutions, J. Mol. Liq. 417, 126673 (2025).
  71. P. La Francesca and P. Gallo, Molecular dynamics simulations of supercooled aqueous solutions of calcium perchlorate: Thermodynamics and structure of Martian solutes in TIP4P/2005 water, J. Phys. Chem. B 129, 8776 (2025).
  72. M. Allen, D. Tildesley, and D. Tildesley, Computer Simulation of Liquids, Oxford Science Publications (Oxford University Press, Oxford, UK, 2017).
  73. B. Hess, C. Kutzner, D. van der Spoel, and E. Lindahl, Gromacs 4: Algorithms for highly efficient, load-balanced, and scalable molecular simulation, J. Chem. Theory Comput. 4, 435 (2008).
  74. H. J. Berendsen, D. van der Spoel, and R. van Drunen, Gromacs: A message-passing parallel molecular dynamics implementation, Comput. Phys. Commun. 91, 43 (1995).
  75. J. L. Abascal and C. Vega, A general purpose model for the condensed phases of water: TIP4P/2005, J. Chem. Phys. 123, 234505 (2005).
  76. I. M. Zeron, J. L. F. Abascal, and C. Vega, A force field of Li+, Na+, K+, Mg2+, Ca2+, Cl−, and SO42− in aqueous solution based on the TIP4P/2005 water model and scaled charges for the ions, J. Chem. Phys. 151, 134504 (2019).
  77. S. Blazquez, J. Troncoso, P. La Francesca, P. Gallo, M. Conde, and C. Vega, Extending the Madrid-2019 force field to the perchlorate anion: Role of charge distribution and validation with experiments on Mars-relevant aqueous solutions, J. Mol. Liq. 435, 128035 (2025).
  78. B. Hess, P-LINCS: A parallel linear constraint solver for molecular simulation, J. Chem. Theory Comput. 4, 116 (2008).
  79. U. Essmann, L. Perera, M. L. Berkowitz, T. Darden, H. Lee, and L. G. Pedersen, A smooth particle mesh Ewald method, J. Chem. Phys. 103, 8577 (1995).
  80. G. Bussi, D. Donadio, and M. Parrinello, Canonical sampling through velocity rescaling, J. Chem. Phys. 126, 014101 (2007).
  81. M. Parrinello and A. Rahman, Crystal structure and pair potentials: A molecular-dynamics study, Phys. Rev. Lett. 45, 1196 (1980).
  82. M. Parrinello and A. Rahman, Polymorphic transitions in single crystals: A new molecular dynamics method, J. Appl. Phys. 52, 7182 (1981).
  83. S. E. Lauro, E. Pettinelli, G. Caprarelli, J. Baniamerian, E. Mattei, B. Cosciotti, D. E. Stillman, K. M. Primm, F. Soldovieri, and R. Orosei, Using MARSIS signal attenuation to assess the presence of South Polar Layered Deposit subglacial brines, Nat. Commun. 13, 5686 (2022).
  84. G. Franzese and H. E. Stanley, The Widom line of supercooled water, J. Phys.: Condens. Matter 19, 205126 (2007).
  85. L. Xu, P. Kumar, S. V. Buldyrev, S.-H. Chen, P. H. Poole, F. Sciortino, and H. E. Stanley, Relation between the Widom line and the dynamic crossover in systems with a liquid–liquid phase transition, Proc. Natl. Acad. Sci. USA 102, 16558 (2005).
  86. J. L. Abascal and C. Vega, Widom line and the liquid–liquid critical point for the TIP4P/2005 water model, J. Chem. Phys. 133, 234502 (2010).
  87. J. R. Errington and P. G. Debenedetti, Relationship between structural order and the anomalies of liquid water, Nature (London) 409, 318 (2001).

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Phys. Rev. E 114, 035416– Published 15 September, 2026
  • Received 12 February 2026
  • Accepted 17 August 2026
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