Observation of plasmons in 2-D organic metal BO2.4I3 by reflection spectroscopy

For the first time the plasmon in 2-D organic metal BO2.4I3 was observed by means of reflection method. The new unknown peak in the near-infrared regi on at 5000 cm(-1) was observed in the specular reflection normal to the ((1 ) over bar 01) crystal face, which makes an angle of 67.0 degrees with the conducting sheet. Such spectrum can be theoretically simulated using the pr incipal dielectric function for a two-dimensional metal. The simulated spec trum agrees well with the experimental one, proving that this new peak is d ue to the plasmon absorption. Similar plasmon absorption we have observed f or BO2Cl(H2O)(3) crystal.