### Abstract

We report high-resolution far-infrared transmittance measurements and quantum-molecular-dynamics calculations of the two-dimensional tetragonal (T) high-temperature/high-pressure (formula presented) polymer, as a complement to our previous work on the (formula presented) dimer, and the one-dimensional orthorhombic (O) and two-dimensional rhombohedral (formula presented) polymers [V. C. Long et al., Phys. Rev. B 61, 13 191 (2000)]. The spectral features are assigned as intramolecular modes according to our quantum-molecular-dynamics calculations. In addition, we determine the (formula presented) parent symmetry of each polymer vibrational mode by expanding the calculated polymer eigenvectors in terms of our calculated eigenvectors for (formula presented) We find that many of the T-polymer vibrational modes are derived from more than one (formula presented) parent symmetry, confirming that a weak perturbation model is inadequate for these covalently bonded (formula presented) balls. In particular, strongly infrared-active T-polymer modes with frequencies of 606 and (formula presented) parent modes. As in the O and R polymers, modes of the T polymer with substantial (formula presented) character, which are polarized in the stretched directions, are found to have large downshifts. Finally, in our comparison of theory with experiment, we find indications that the in-plane lattice of the T polymer may not actually be square.

Original language | English |
---|---|

Pages (from-to) | 1-9 |

Number of pages | 9 |

Journal | Physical Review B - Condensed Matter and Materials Physics |

Volume | 65 |

Issue number | 8 |

DOIs | |

Publication status | Published - Jan 1 2002 |

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### ASJC Scopus subject areas

- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics

### Cite this

*Physical Review B - Condensed Matter and Materials Physics*,

*65*(8), 1-9. https://doi.org/10.1103/PhysRevB.65.085413

**Far-infrared vibrational properties of tetragonal (formula presented) polymer.** / Zhu, Z. T.; Musfeldt, J. L.; Kamarás, K.; Adams, G. B.; Page, J. B.; Davydov, V. A.; Kashevarova, L. S.; Rakhmanina, A. V.

Research output: Contribution to journal › Article

*Physical Review B - Condensed Matter and Materials Physics*, vol. 65, no. 8, pp. 1-9. https://doi.org/10.1103/PhysRevB.65.085413

}

TY - JOUR

T1 - Far-infrared vibrational properties of tetragonal (formula presented) polymer

AU - Zhu, Z. T.

AU - Musfeldt, J. L.

AU - Kamarás, K.

AU - Adams, G. B.

AU - Page, J. B.

AU - Davydov, V. A.

AU - Kashevarova, L. S.

AU - Rakhmanina, A. V.

PY - 2002/1/1

Y1 - 2002/1/1

N2 - We report high-resolution far-infrared transmittance measurements and quantum-molecular-dynamics calculations of the two-dimensional tetragonal (T) high-temperature/high-pressure (formula presented) polymer, as a complement to our previous work on the (formula presented) dimer, and the one-dimensional orthorhombic (O) and two-dimensional rhombohedral (formula presented) polymers [V. C. Long et al., Phys. Rev. B 61, 13 191 (2000)]. The spectral features are assigned as intramolecular modes according to our quantum-molecular-dynamics calculations. In addition, we determine the (formula presented) parent symmetry of each polymer vibrational mode by expanding the calculated polymer eigenvectors in terms of our calculated eigenvectors for (formula presented) We find that many of the T-polymer vibrational modes are derived from more than one (formula presented) parent symmetry, confirming that a weak perturbation model is inadequate for these covalently bonded (formula presented) balls. In particular, strongly infrared-active T-polymer modes with frequencies of 606 and (formula presented) parent modes. As in the O and R polymers, modes of the T polymer with substantial (formula presented) character, which are polarized in the stretched directions, are found to have large downshifts. Finally, in our comparison of theory with experiment, we find indications that the in-plane lattice of the T polymer may not actually be square.

AB - We report high-resolution far-infrared transmittance measurements and quantum-molecular-dynamics calculations of the two-dimensional tetragonal (T) high-temperature/high-pressure (formula presented) polymer, as a complement to our previous work on the (formula presented) dimer, and the one-dimensional orthorhombic (O) and two-dimensional rhombohedral (formula presented) polymers [V. C. Long et al., Phys. Rev. B 61, 13 191 (2000)]. The spectral features are assigned as intramolecular modes according to our quantum-molecular-dynamics calculations. In addition, we determine the (formula presented) parent symmetry of each polymer vibrational mode by expanding the calculated polymer eigenvectors in terms of our calculated eigenvectors for (formula presented) We find that many of the T-polymer vibrational modes are derived from more than one (formula presented) parent symmetry, confirming that a weak perturbation model is inadequate for these covalently bonded (formula presented) balls. In particular, strongly infrared-active T-polymer modes with frequencies of 606 and (formula presented) parent modes. As in the O and R polymers, modes of the T polymer with substantial (formula presented) character, which are polarized in the stretched directions, are found to have large downshifts. Finally, in our comparison of theory with experiment, we find indications that the in-plane lattice of the T polymer may not actually be square.

UR - http://www.scopus.com/inward/record.url?scp=85038282070&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85038282070&partnerID=8YFLogxK

U2 - 10.1103/PhysRevB.65.085413

DO - 10.1103/PhysRevB.65.085413

M3 - Article

AN - SCOPUS:85038282070

VL - 65

SP - 1

EP - 9

JO - Physical Review B-Condensed Matter

JF - Physical Review B-Condensed Matter

SN - 0163-1829

IS - 8

ER -