Zero-field magnetic resonance of the photo-excited triplet state of pentacene at room temperature

Abstract

The pulsed EPR free induction decay (FID) signals of the photo-excited pentacene triplet state are reported for three mixed crystals at room temperature: pentacene-h14 in p-terphenyl, pentacene-h14 in benzoic acid, and pentacene-d14 in p-terphenyl. The recorded FID signals have relatively long decay times of about four microseconds, presumably due to the reduced hyperfine interactions in the zero magnetic field. The time domain FID signals transform to spectral components typically narrower than 500 kHz, allowing us to determine the pentacene triplet zero field splitting parameters to better accuracy than previously reported. Further, a new experimental technique using the high speed magnetic field jumping capability enables us to examine the anisotropic hyperfine and quadrupole interactions.

Room-temperature cavity quantum electrodynamics with strongly coupled Dicke states

“…An estimate of the ensemble spin-photon coupling strength is therefore g e g s ffiffiffi ffi N p % 2π 1:1 MHz. The cavity mode decay rate (linewidth) was measured to be κ c = 2π × 0.18 MHz and the spin decoherence rate of the transition was taken from reported roomtemperature free induction decay measurements of the spin dephasing time for samples of similar concentration, T Ã 2 ¼ 2:9 μs, 21 yielding a rate of κ s ¼ 2=T Ã 2 % 2π 0:11 MHz. The spin-lattice relaxation rate and decay rates of the triplet sub-levels back to the singlet ground state are at least an order of magnitude slower than the spin dephasing rate so can be neglected.…”

Orientational anisotropic studies by field rotation technique: Near zero-field pulsed EPR experiments of pentacene doped in p-terphenyl

“…Previously, we reported a zero-field (ZF) pulsed electron paramagnetic resonance (EPR) study of the photoexcited triplet state of pentacene in mixed crystal systems [1]. The spin dipolar interaction between two electron spins of the S = 1 system gives rise to the ZF splitting.…”

Proton spin system in pentacene and its interaction with photoexcited triplet electron spin

“…This is due to a peculiar properties of the intersystem crossing process triplet exciting state of pentacene (as a great spin-orbit coupling, long living time etc.). For this system many experimental results are already accessible [1,11]. Our results (Bethe solutions) presented in this paper describe in exact way the proton spin system of the pentacene molecule.…”

“…These spins interact with electron triplet spin via hyperfine interaction (HFI). Experimentally, the subject was studied by isotopic effects [11,12]. The HFI determines the shape of the magnetic resonance line in ODMRS experiment as well.…”

“…Recently, the nitrogen-vacancy centers in diamond [7,8] were declared to be a better quantum system for information processing [1,9]. However, the study of the single pentacene molecule is still actual due to possibility of experimental measure and verification of several quantum-mechanical principles (as spin coherence [10], room temperature measurements of fine structure of the intersystem crossing process ISC [11], spin diffusion as well as preparation of initial state [1]), which are very important for realisation of quantum algorithms.…”