Heat capacity anomalies of the molecular crystal 1-fluoro-adamantane at low temperatures
Abstract Disorder–disorder phase transitions are rare in nature. Here, we present a comprehensive low-temperature experimental and theoretical study of the heat capacity and vibrational density of states of 1-fluoro-adamantane (C10H15F), an intriguing molecular crystal that presents a continuous dis...
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| Format: | Article |
| Language: | English |
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Nature Portfolio
2021-09-01
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| Series: | Scientific Reports |
| Online Access: | https://doi.org/10.1038/s41598-021-97973-2 |
| _version_ | 1818425640593915904 |
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| author | Daria Szewczyk Jonathan F. Gebbia Andrzej Jeżowski Alexander I. Krivchikov Tatiana Guidi Claudio Cazorla Josep-Lluís Tamarit |
| author_facet | Daria Szewczyk Jonathan F. Gebbia Andrzej Jeżowski Alexander I. Krivchikov Tatiana Guidi Claudio Cazorla Josep-Lluís Tamarit |
| author_sort | Daria Szewczyk |
| collection | DOAJ |
| description | Abstract Disorder–disorder phase transitions are rare in nature. Here, we present a comprehensive low-temperature experimental and theoretical study of the heat capacity and vibrational density of states of 1-fluoro-adamantane (C10H15F), an intriguing molecular crystal that presents a continuous disorder–disorder phase transition at T = 180 K and a low-temperature tetragonal phase that exhibits fractional fluorine occupancy. It is shown that fluorine occupancy disorder in the low-T phase of 1-fluoro-adamantane gives rise to the appearance of low-temperature glassy features in the corresponding specific heat (i.e., “boson peak” -BP-) and vibrational density of states. We identify the inflation of low-energy optical modes as the main responsible for the appearance of such glassy heat-capacity features and propose a straightforward correlation between the first localized optical mode and maximum BP temperature for disordered molecular crystals (either occupational or orientational). Thus, the present study provides new physical insights into the possible origins of the BP appearing in disordered materials and expands the set of molecular crystals in which “glassy-like” heat-capacity features have been observed. |
| first_indexed | 2024-12-14T14:17:09Z |
| format | Article |
| id | doaj.art-2b484f4e0964463881dd483afef2485c |
| institution | Directory Open Access Journal |
| issn | 2045-2322 |
| language | English |
| last_indexed | 2024-12-14T14:17:09Z |
| publishDate | 2021-09-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | Scientific Reports |
| spelling | doaj.art-2b484f4e0964463881dd483afef2485c2022-12-21T22:58:10ZengNature PortfolioScientific Reports2045-23222021-09-011111810.1038/s41598-021-97973-2Heat capacity anomalies of the molecular crystal 1-fluoro-adamantane at low temperaturesDaria Szewczyk0Jonathan F. Gebbia1Andrzej Jeżowski2Alexander I. Krivchikov3Tatiana Guidi4Claudio Cazorla5Josep-Lluís Tamarit6Institute of Low Temperature and Structure Research PASGrup de Caracterització de Materials, Departament de Física, EEBE and Research Center in Multiscale Science and Engineering, Universitat Politècnica de CatalunyaInstitute of Low Temperature and Structure Research PASB. Verkin Institute for Low Temperature Physics and Engineering, NAS of UkraineISIS Facility, Rutherford Appleton LaboratoryDepartament de Física, Universitat Politècnica de CatalunyaGrup de Caracterització de Materials, Departament de Física, EEBE and Research Center in Multiscale Science and Engineering, Universitat Politècnica de CatalunyaAbstract Disorder–disorder phase transitions are rare in nature. Here, we present a comprehensive low-temperature experimental and theoretical study of the heat capacity and vibrational density of states of 1-fluoro-adamantane (C10H15F), an intriguing molecular crystal that presents a continuous disorder–disorder phase transition at T = 180 K and a low-temperature tetragonal phase that exhibits fractional fluorine occupancy. It is shown that fluorine occupancy disorder in the low-T phase of 1-fluoro-adamantane gives rise to the appearance of low-temperature glassy features in the corresponding specific heat (i.e., “boson peak” -BP-) and vibrational density of states. We identify the inflation of low-energy optical modes as the main responsible for the appearance of such glassy heat-capacity features and propose a straightforward correlation between the first localized optical mode and maximum BP temperature for disordered molecular crystals (either occupational or orientational). Thus, the present study provides new physical insights into the possible origins of the BP appearing in disordered materials and expands the set of molecular crystals in which “glassy-like” heat-capacity features have been observed.https://doi.org/10.1038/s41598-021-97973-2 |
| spellingShingle | Daria Szewczyk Jonathan F. Gebbia Andrzej Jeżowski Alexander I. Krivchikov Tatiana Guidi Claudio Cazorla Josep-Lluís Tamarit Heat capacity anomalies of the molecular crystal 1-fluoro-adamantane at low temperatures Scientific Reports |
| title | Heat capacity anomalies of the molecular crystal 1-fluoro-adamantane at low temperatures |
| title_full | Heat capacity anomalies of the molecular crystal 1-fluoro-adamantane at low temperatures |
| title_fullStr | Heat capacity anomalies of the molecular crystal 1-fluoro-adamantane at low temperatures |
| title_full_unstemmed | Heat capacity anomalies of the molecular crystal 1-fluoro-adamantane at low temperatures |
| title_short | Heat capacity anomalies of the molecular crystal 1-fluoro-adamantane at low temperatures |
| title_sort | heat capacity anomalies of the molecular crystal 1 fluoro adamantane at low temperatures |
| url | https://doi.org/10.1038/s41598-021-97973-2 |
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