Phosphorescence from phenazine in alkane solvents in the glass transition range: Spin-lattice, environment, and orientation relaxation of molecules in the metastable triplet state

Journal Article · Thu Mar 07 04:00:00 EST 1991 · Journal of Physical Chemistry; (USA)

DOI:https://doi.org/10.1021/j100158a026· OSTI ID:5679446

Nickel, B; Ruth, A A ^[1]

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1. Max-Planck-Institut fuer Biophysikalische Chemie, Goettingen (West Germany)

The phosphorescence from phenazine in two similar solvents was investigated in the glass transition range with the aim to find a correlation between spin-lattice relaxation (SLR) of molecules in the metastable triplet state (T{sub 1}) and their orientational relaxation (OR). The solvents were 3-methylpentane (3MeP) and a 1:1 mixture of 3-methylpentane and isopentane (3MeP/IP). Upon laser flash excitation, apart from the decay of the total population of T{sub 1}, three relaxation processes of molecules in T{sub 1} were detected: (1) the decay of the selective population of the strongly phosphorescent triplet substate T{sub 1x} due to SLR, (2) a time-dependent red shift of the phosphorescence spectrum resulting from molecular environment relaxation (MER), (3) the decay of the phosphorescence polarization due to OR. All three relaxation process are in 3MeP slower than in the less viscous solvent 3MeP/IP, but a simple relation between OR and SLR has not been found. The temperature dependence of the SLR rate constant can be represented by the sum of two terms: a T{sup 7} or Arrhenius term dominant at low temperatures (SLR{sub 1}) and an Arrhenius term dominant at high temperatures (SLR{sub h}). SLR{sub 1} is assigned to SLR processes characteristic for a hard glass, and SLR{sub h} is assigned to SLR resulting from rotational diffusion.

• OSTI ID: 5679446
• Journal Information: Journal of Physical Chemistry; (USA), Journal Name: Journal of Physical Chemistry; (USA) Vol. 95:5; ISSN 0022-3654; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
AZINES
DATA
DATA ANALYSIS
ENERGY LEVELS
EXCITED STATES
EXPERIMENTAL DATA
HETEROCYCLIC COMPOUNDS
INFORMATION
LUMINESCENCE
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHENAZINE
PHOSPHORESCENCE
PYRAZINES
RELAXATION
SPIN-LATTICE RELAXATION
TEMPERATURE DEPENDENCE