Open AccessProbing of Higher Excited States of Merocyanine Derivatives of Azaazulene and Indandione by Fluorescence Excitation Anisotropy Spectra
Author(s) -
A. P. Naumenko,
V. I. Borysuk,
Marianna Iakhnenko,
V. O. Gubanov,
Yu. L. Slominskii,
O.D. Kachkovsky
Publication year - 2020
Publication title -
ukrainian journal of physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.213
H-Index - 17
eISSN - 2071-0194
pISSN - 2071-0186
DOI - 10.15407/ujpe65.4.321
Subject(s) - delocalized electron , excited state , anisotropy , bathochromic shift , molecular electronic transition , fluorescence , chromophore , excitation , spectral line , fluorescence anisotropy , atomic electron transition , merocyanine , chemistry , photochemistry , molecular physics , materials science , atomic physics , physics , optics , photochromism , organic chemistry , quantum mechanics , astronomy
This paper is dedicated to the spectral and quantum-chemical studies of higher excited states of merocyanine derivatives of azaazulene and indandione. A particular attention is paid to the analysis of fluorescence excitation anisotropy spectra of the mentioned compounds. The long-wave shift by ≈ 50 nm of a deep clear minimum in the fluorescence excitation anisotropy spectrum due to an elongation of the polymethine dye chromophore is established. Such shift is close in a value to the bathochromic shift of the first minimum in the anisotropy spectrum of symmetric ionic polymethine dyes, in which this minimum corresponds to the second electronic transition. The parallel spectral study and quantum-chemical calculations allowed us to correctly interpret the fluorescence excitation anisotropy spectra of merocyanines and relate the first clear minimum with the seventh electronic transition. The last resembles the second electronic transition between delocalized molecular orbitals (MO) in polymethine dyes.