D.S. Tinti

Correlation of the zero field splittings with the phosphorescence rate constants and vibronic activity in the lowest triplet state of benzaldehydes by PMDR

Abstract Phosphorescence-microwave double-resonance (PMDR) techniques are used to measure the zero field splittings and the phosphorescence rate constants of individual spin levels in the lowest triplet state of benzaldehyde and several para-substituted benzaldehydes. The nature of the triplet state is discussed in terms of the spin splittings, the vibronic activity in the phosphorescence spectrum, and the phosphorescence rate constants.

PMDR studies of intramolecular spin-orbit perturbations on the triplet state properties of substituted benzenes

Abstract PMDR studies on a series of halobenzenes have shown that the in-plane electron spin distribution is highly perturbable and that spin-orbit contributions to the relative energies of the spin states become significant in the heavier halobenzenes. A distortion in the triplet state of the heavier dihalobenzenes is also indicated.

Assignment of the lowest triplet state of benzene using phosphorescence-microwave double resonance (PMDR) techniques

Abstract Phosphorescence-microwave double resonance (PMDR) techniques are used and the zero-field (zf) origin of the 0, 0 band of the phosphorescence of benzene-h6 in benzene-d6 at 1.6°K is determined to be the τy level. This is consistent with a 3B1u assignment for a distorted D2h benzene in its triplet state and contradicts a recently suggested 3B2u assignment.

Phosphorescence-microwave double-resonance studies of 1,3-, 1,5-, and 1,8-diazanaphthalene

Abstract Phosphorescence-microwave double-resonance techniques are employed at T ≲ 4.2°K to measure the zero field splittings and the kinetic parameters for population and depopulation of the phosphorescing triplet state of 1,3-, 1,5-, and 1,8-diazanaphthalene in a durene host crystal.

Spin-orbit perturbation of the anion states by a heavy cation in NaNO2:Ag+

Optical and ODMR studies of NaNO2: Ag+ crystals at T < 4.2 K have shown very selective spin-orbit perturbations on the properties of the nitrite triplet state T1, by the heavy cation dopant. The perturbed T1 — S0 transition shows mainly z-axis polarization associated with the τy spin state (z- and y-axes in-plane with the z-axis bisecting the ONO angle). The fine structure splitting constants for the perturbed T1 state are D = -3Y/2 = ± 15.508 GHz and E = (Z - X)/2 = ‡ .643 GHz.

Polarization measurements in optically detected electron spin resonance of excited triplet states at zero field

Abstract Polarization measurements of optically detected electron spin resonance at zero field using an external antenna to transmit linearly polarized microwave power are described.

Optical detection of the zero field splittings in the phosphorescent triplet state of neat SO2 crystals

Abstract The zero field transition energies in the phosphorescent triplet state of neat SO 2 are directly measured by optical detection at 1.4°K, leading to | D | = 0.275 cm −1 and | E | = 0.0157 5 cm −1 for the usual spin hamiltonian parameters. Two spin states are found to be active in the phosphorescence with the dominant spin state having a lifetime of 2 msec.

The lowest excited states of a chromate derivative. Resolved optical and odmr spectra of RbCrO3Cl AND CsCrO3Cl at 1.4 K

The phosphorescence, excitation and absorption spectra of the CrO3Cl− anion in its neat rubidium and cesium salts at 1.4 K are reported. The spectra show sharp zero-phonon lines, which allow vibronic analyses of the phosphorescence spectra based on the respective Raman spectra. The zero-field splittings and lifetimes of the spin-triplet state of CrO3Cl− anion in each of the salts have also been obtained. The results are compared with earlier results for the potassium salt.

The lowest triplet state of CrO2Cl2. Emission and excitation spectra

Abstract The emission and excitation spectra at 1.4 K of solid neat CrO2Cl2, CrO2Cl2 in CCl4 and CrO2Cl2 in SnCl4 are reported and analyzed. The emission in the three systems is assigned as phosphorescence from the CrO2Cl2 moiety based on the vibronic analyses, measured lifetimes and ODMR activity.

ODMR spectra of randomly oriented triplet states in a low Zeeman field

Abstract The frequency swept ODMR spectra expected for a randomly oriented triplet state in a low Zeeman field are described. Relative to the zero-field spectra, the perturbations induced by a rather low field are sufficient to allow the determination of the magnitudes of the zero-field splitting constants when only two of the three possible spin transitions are observed. The techniques is demonstrated for the triplet state of C 2 O 2− 4 and applied to the triplet state of CrO 2 Cl 2 .