INTENSITIES OF 2-PHOTON ABSORPTIONS TO LOW-LYING EVEN-PARITY STATES IN LINEAR-CHAIN CONJUGATED POLYMERS
INTENSITIES OF 2-PHOTON ABSORPTIONS TO LOW-LYING EVEN-PARITY STATES IN LINEAR-CHAIN CONJUGATED POLYMERS
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DOI：
10.1103/physrevb.49.10102
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发表时间：
1994-04-15
影响因子：
3.7
通讯作者：
MAZUMDAR, S
中科院分区：
文献类型：
--
作者：
GUO, F;GUO, D;MAZUMDAR, S
在直链π共轭聚合物中，对最低偶宇称双光子态的兴趣主要限于它们相对于最低奇宇称单光子态的能量。我们发现，在无限长链中，由于抵消作用，在最低单光子态以下发生的双光子对偶宇称态的散射强度应该很小。这对解释聚二乙炔的三次谐波产生光谱具有重要意义。在聚二乙炔的三次谐波产生中看到的共振通常被分配为双光子共振，在这里被解释为三光子共振。
Interest in the lowest even-parity two-photon states in linear-chain pi-conjugated polymers has been largely limited to their energies relative to the lowest odd-parity one-photon state. We show that the intensities of the two-photon absorptions to even-parity states that occur below the lowest one-photon states should be tiny in the infinite chain, because of cancellations. This has important implications for the interpretation of third-harmonic generation spectra of polydiacetylenes. A resonance seen in third-harmonic generation of polydiacetylenes that has commonly been assigned as a two-photon resonance is interpreted here as a three-photon resonance.