vibrational spectra of β″-type bedt-ttf salts relationship between conducting property, time-averaged site charge and inter-molecular distance振动光谱β.pdfVIP

Crystals 2012, 2, 893-934; doi:10.3390/cryst2030893 OPEN ACCESS crystals ISSN 2073-4352 /journal/crystals Review Vibrational Spectra of β″-Type BEDT-TTF Salts: Relationship between Conducting Property, Time-Averaged Site Charge and Inter-Molecular Distance Takashi Yamamoto Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan; E-Mail: yamataka@chem.sci.osaka-u.ac.jp; Tel.: +81-6-6850-5399; Fax: +81-6-6850-6797 Received: 18 April 2012; in revised form: 20 June 2012 / Accepted: 26 June 2012 / Published: 6 July 2012 Abstract: The relationship between the conducting behavior and the degree of charge fluctuation in the β″-type BEDT-TTF salts is reviewed from the standpoints of vibrational spectroscopy and crystal structure. A group of β″-type ET salts demonstrates the best model compounds for achieving the above relationship because the two-dimensional structure is simple and great diversity in conducting behavior is realized under ambient pressure. After describing the requirement for the model compound, the methodology for analyzing the results of the vibrational spectra is presented. Vibrational spectroscopy provides the time-averaged molecular charge, the charge distribution in the two- dimensional layer, and the inter-molecular interactions, etc. The experimental results applied to 2/3-filled and 3/4-filled β″-type ET salts are repo