Mid-infrared absorption and Raman spectra of the geometrically frustrated material series, hydroxyl cobalt halides β-CO2（OH）3Cl and β-CO2（OH）3Br, are first, to the best of our knowledge, measured at room tempera...Mid-infrared absorption and Raman spectra of the geometrically frustrated material series, hydroxyl cobalt halides β-CO2（OH）3Cl and β-CO2（OH）3Br, are first, to the best of our knowledge, measured at room temperature, to study the corresponding relationship between their vibrational spectral properties and crystal microstructures. Through the comparative analysis of the four spectra we have categorically assigned the OH-related vibration modes of hydroxyl groups in the trimeric hydrogen bond environment （Co3 =OH）3 … Cl/Br, and tentatively suggested vibration modes of O-Co-O, Co O and Cl/Br-Co-Cl/Br units. These results can also become the basis for analysing their low-temperature spectral properties, which can help to understand the underlying physics of their exotic geometric frustration phenomena around phase transition temperatures.展开更多
Raman vibrational spectra of the selected basic （hydroxyl OH and deuteroxyl OD） transition-metal halides, geomet- rically frustrated material series α-, β-, γ-Cu2（OH）3Cl, α-Cu2（OH）3Br, β-Ni2（OH）3Cl, β-Co...Raman vibrational spectra of the selected basic （hydroxyl OH and deuteroxyl OD） transition-metal halides, geomet- rically frustrated material series α-, β-, γ-Cu2（OH）3Cl, α-Cu2（OH）3Br, β-Ni2（OH）3Cl, β-Co2（OH）3Cl, β-Co2（OH）3Br, γ-Cu2（OD）3Cl, and β-Co2（OD）3Cl are measured at room temperature and analysed to investigate the relationship be- tween the microstructured OH environments and their respective Raman spectra. Among these selected samples, the last two are used to determine the OH stretching vibration region （3600 cm-1-3300 cm-1） and OH bending vibra- tion region （1000 cm-1-600 cm-1） of OH systems in the spectra. Through the comparative analysis of the distances d（metal-O）, d（O-halogen）, and d（OH）, the strong metal-O interaction and trimeric hydrogen bond （Car, C8 or C1 symmetry） are found in every material, but both determine simultaneously an ultimate d（OH）, and therefore an OH stretching vibration frequency. According to the approximately linear relationship between the OH stretching vibration frequency and d（OH）, some unavailable d（OH） are guessed and some doubtful d（OH） are suggested to be corrected. In addition, it is demonstrated in brief that the OH bending vibration frequency is also of importance to check the more detailed crystal microstructure relating to the OH group.展开更多
Vibrational spectra(Raman 4000–95 cm−1 and mid-IR 4000–400 cm−1)of the atacamite-structure Ni_(2)(OH)3Cl,including a rarely reported kind of asymmetric trimetric hydrogen bond,as a member of the geometrically frustr...Vibrational spectra(Raman 4000–95 cm−1 and mid-IR 4000–400 cm−1)of the atacamite-structure Ni_(2)(OH)3Cl,including a rarely reported kind of asymmetric trimetric hydrogen bond,as a member of the geometrically frustrated material series and its deuteride Ni_(2)(OD)3Cl are,to the best of our knowledge,reported for the first time and analyzed at room temperature.Through a comparative study of four spectra according to their crystal structural parameters,we assign OH stretching modes v(OH)in a functional group region(3700–3400 cm−1)and their deformation modesδ(NiOH/D)in the correlation peak region(900–600 cm−1)with the corresponding mode frequency ratiosωv(OD)/ωv(OH)≈73%andωδ(NiOD)/ωδ(NiOH)≈75%,and further self−consistently suggest Ni-O and Ni-Cl related modes in the fingerprint region(500–200 cm^(−1) and 200–0 cm−1,respectively)by use of the unified six-ligand NiO_(5)Cl and NiO_(4)Cl_(2) frames.This report may contribute to the spectral analysis of other hydroxyl transition-metal halides and to the understanding of the fundamental physics of their exotic magnetic geometrical frustration property from the spectral changes around the corresponding low transition temperatures.展开更多
基金Project supported by the Grant-in-Aid for Scientific Research from the Japanese Society for the Promotion of Science (Grant No.Kiban-B 19340100)the Grant-in-Aid for Scientific Research on Priority Areas from the Ministry of Education,Culture,Sports,Science and Technology,Japan (Grant No.Tokutei 22014008)
文摘Mid-infrared absorption and Raman spectra of the geometrically frustrated material series, hydroxyl cobalt halides β-CO2（OH）3Cl and β-CO2（OH）3Br, are first, to the best of our knowledge, measured at room temperature, to study the corresponding relationship between their vibrational spectral properties and crystal microstructures. Through the comparative analysis of the four spectra we have categorically assigned the OH-related vibration modes of hydroxyl groups in the trimeric hydrogen bond environment （Co3 =OH）3 … Cl/Br, and tentatively suggested vibration modes of O-Co-O, Co O and Cl/Br-Co-Cl/Br units. These results can also become the basis for analysing their low-temperature spectral properties, which can help to understand the underlying physics of their exotic geometric frustration phenomena around phase transition temperatures.
基金Project supported by the Grant-in-Aid for Scientific Research on Priority Area from the Ministry of Education,Culture,Sports,Science and Technology,Japan (Grant No. Tokutei 22014008)
文摘Raman vibrational spectra of the selected basic （hydroxyl OH and deuteroxyl OD） transition-metal halides, geomet- rically frustrated material series α-, β-, γ-Cu2（OH）3Cl, α-Cu2（OH）3Br, β-Ni2（OH）3Cl, β-Co2（OH）3Cl, β-Co2（OH）3Br, γ-Cu2（OD）3Cl, and β-Co2（OD）3Cl are measured at room temperature and analysed to investigate the relationship be- tween the microstructured OH environments and their respective Raman spectra. Among these selected samples, the last two are used to determine the OH stretching vibration region （3600 cm-1-3300 cm-1） and OH bending vibra- tion region （1000 cm-1-600 cm-1） of OH systems in the spectra. Through the comparative analysis of the distances d（metal-O）, d（O-halogen）, and d（OH）, the strong metal-O interaction and trimeric hydrogen bond （Car, C8 or C1 symmetry） are found in every material, but both determine simultaneously an ultimate d（OH）, and therefore an OH stretching vibration frequency. According to the approximately linear relationship between the OH stretching vibration frequency and d（OH）, some unavailable d（OH） are guessed and some doubtful d（OH） are suggested to be corrected. In addition, it is demonstrated in brief that the OH bending vibration frequency is also of importance to check the more detailed crystal microstructure relating to the OH group.
基金by a Grant-in-Aid for Scientific Research from the Japan Society for the Promotion of Science under Grant (No Kiban-B 19340100)Grant-in-Aid for Scientific Research on Priority Areas(No Tokutei 22014008)from the Ministry of Education,Culture,Sports,Science and Technology,Japan.
文摘Vibrational spectra(Raman 4000–95 cm−1 and mid-IR 4000–400 cm−1)of the atacamite-structure Ni_(2)(OH)3Cl,including a rarely reported kind of asymmetric trimetric hydrogen bond,as a member of the geometrically frustrated material series and its deuteride Ni_(2)(OD)3Cl are,to the best of our knowledge,reported for the first time and analyzed at room temperature.Through a comparative study of four spectra according to their crystal structural parameters,we assign OH stretching modes v(OH)in a functional group region(3700–3400 cm−1)and their deformation modesδ(NiOH/D)in the correlation peak region(900–600 cm−1)with the corresponding mode frequency ratiosωv(OD)/ωv(OH)≈73%andωδ(NiOD)/ωδ(NiOH)≈75%,and further self−consistently suggest Ni-O and Ni-Cl related modes in the fingerprint region(500–200 cm^(−1) and 200–0 cm−1,respectively)by use of the unified six-ligand NiO_(5)Cl and NiO_(4)Cl_(2) frames.This report may contribute to the spectral analysis of other hydroxyl transition-metal halides and to the understanding of the fundamental physics of their exotic magnetic geometrical frustration property from the spectral changes around the corresponding low transition temperatures.
