Structure and short timescale ion dynamics of potassium-ammonia graphite intercalation compounds
We present Generalized Gradient Corrected Density Functional Theory (DFT) calculations of the static and dynamic properties of stage-I potassium and potassium-ammonia graphite intercalation compounds KC8 and KC24(NH3)x, with x = 0, 1, 2, 3, 4, 4.5, 5. For each system, a full geometry optimization wa...
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| Format: | Journal article |
| Language: | English |
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2002
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| _version_ | 1797092563674464256 |
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| author | Bernasconi, L Madden, P |
| author_facet | Bernasconi, L Madden, P |
| author_sort | Bernasconi, L |
| collection | OXFORD |
| description | We present Generalized Gradient Corrected Density Functional Theory (DFT) calculations of the static and dynamic properties of stage-I potassium and potassium-ammonia graphite intercalation compounds KC8 and KC24(NH3)x, with x = 0, 1, 2, 3, 4, 4.5, 5. For each system, a full geometry optimization was carried out, and finite temperature first-principle molecular dynamics (FPMD) simulations were performed on a selected number of compounds (KC8, KC24, KC24(NH3)4, and KC24(NH3)5) in the temperature range 373-573 K and overall simulation times of 2-4 ps. K was found to adsorb preferentially above C6 rings and, typically, to diffuse parallel to the ab-plane at finite temperature. In addition, a slow oscillatory motion perpendicular to the carbon layers was observed, with K residing in turn closer to one or another carbon plane. We speculate on these findings in their connection with the electronic properties of potassium-ammonia intercalates in the vicinity of the metal-nonmetal transition at x ≃ 4.3. |
| first_indexed | 2024-03-07T03:47:45Z |
| format | Journal article |
| id | oxford-uuid:c01ac448-077f-4121-a331-4efc8045c4da |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T03:47:45Z |
| publishDate | 2002 |
| record_format | dspace |
| spelling | oxford-uuid:c01ac448-077f-4121-a331-4efc8045c4da2022-03-27T05:52:09ZStructure and short timescale ion dynamics of potassium-ammonia graphite intercalation compoundsJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:c01ac448-077f-4121-a331-4efc8045c4daEnglishSymplectic Elements at Oxford2002Bernasconi, LMadden, PWe present Generalized Gradient Corrected Density Functional Theory (DFT) calculations of the static and dynamic properties of stage-I potassium and potassium-ammonia graphite intercalation compounds KC8 and KC24(NH3)x, with x = 0, 1, 2, 3, 4, 4.5, 5. For each system, a full geometry optimization was carried out, and finite temperature first-principle molecular dynamics (FPMD) simulations were performed on a selected number of compounds (KC8, KC24, KC24(NH3)4, and KC24(NH3)5) in the temperature range 373-573 K and overall simulation times of 2-4 ps. K was found to adsorb preferentially above C6 rings and, typically, to diffuse parallel to the ab-plane at finite temperature. In addition, a slow oscillatory motion perpendicular to the carbon layers was observed, with K residing in turn closer to one or another carbon plane. We speculate on these findings in their connection with the electronic properties of potassium-ammonia intercalates in the vicinity of the metal-nonmetal transition at x ≃ 4.3. |
| spellingShingle | Bernasconi, L Madden, P Structure and short timescale ion dynamics of potassium-ammonia graphite intercalation compounds |
| title | Structure and short timescale ion dynamics of potassium-ammonia graphite intercalation compounds |
| title_full | Structure and short timescale ion dynamics of potassium-ammonia graphite intercalation compounds |
| title_fullStr | Structure and short timescale ion dynamics of potassium-ammonia graphite intercalation compounds |
| title_full_unstemmed | Structure and short timescale ion dynamics of potassium-ammonia graphite intercalation compounds |
| title_short | Structure and short timescale ion dynamics of potassium-ammonia graphite intercalation compounds |
| title_sort | structure and short timescale ion dynamics of potassium ammonia graphite intercalation compounds |
| work_keys_str_mv | AT bernasconil structureandshorttimescaleiondynamicsofpotassiumammoniagraphiteintercalationcompounds AT maddenp structureandshorttimescaleiondynamicsofpotassiumammoniagraphiteintercalationcompounds |