Phosphorescence-microwave double resonance spectroscopy of 1,2,4,5 tetrachlorobenzene

Technical Report · Sat Apr 01 04:00:00 EST 1972

OSTI ID:6828325

Chen, C R

At very low temperatures (ca. 1.6/sup 0/K), when the spin-lattice relaxation processes between the zero field levels of the lowest triplet state are slow compared to their electronic decay processes to the ground state, the decay constants from and the relative intersystem crossing rate constants to the individual zero field levels of the lowest emitting triplet state can be optically determined. Different perturbations, such as temperature change, application of magnetic field, and saturation of the zero field transition with microwave radiation of resonance frequencies can be applied and new techniques such as amplitude modulation of the phosphorescence-microwave double resonance spectrum, measurement of the polarization of the magnetic transition in zero field, and the delayed microwave pulsing technique can be used to determine the molecular properties of the triplet state. Combining all the results of the above spectroscopic techniques, one can obtain the assignment of the zero field origin of the different vibronic bands, the main spin orbit-vibronic schemes responsible for the phosphorescence process, the mechanism of the intersystem crossing process, the relative signs of the zero field (D and E) parameters, as well as the assignment of the symmetry of the electronic spacial wavefunction of the lowest emitting triplet state. These results are obtained for 1,2,4,5 symmetric tetrachlorobenzene in durene at 1.6/sup 0/K, and the important conclusions are summarized.

• Research Organization: California Univ., Los Angeles (USA). Dept. of Chemistry
• DOE Contract Number: AT03-76ER70091
• OSTI ID: 6828325
• Report Number(s): UCLA-34P91-48
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400301* -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987)
AROMATICS
CHLORINATED AROMATIC HYDROCARBONS
ELECTROMAGNETIC RADIATION
ENERGY LEVELS
EXCITED STATES
HALOGENATED AROMATIC HYDROCARBONS
LUMINESCENCE
MICROWAVE RADIATION
MICROWAVE SPECTRA
MULTIPLETS
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
PHOSPHORESCENCE
RADIATIONS
SPECTRA
SPECTROSCOPY
TRIPLETS
ULTRALOW TEMPERATURE