Phosphorescence from the two triplet states of p-benzoquinone and toluquinone vapour
Phosphorescence from the two triplet states of p-benzoquinone and toluquinone vapour
复制标题
对苯醌和甲苯醌蒸气的两个三重态的磷光
DOI：
10.1080/00268977100100711
复制
发表时间：
1971
影响因子：
1.7
通讯作者：
Y. Kanda
中科院分区：
文献类型：
--
作者：
M. Koyanagi;Y. Kogo;Y. Kanda
The visible emission spectra of p-benzoquinone-h4 (PBQ-h4) and PBQ-d4 were observed in the vapour state in flowing benzene by Jayswal and Singh [1] and assigned to a ZAu-lAg transition by a vibrational analysis [2]. Recently, we have also studied the emission spectrum of PBQ-h4 in an isotopically mixed crystal at 1.45 K and found some important evidence that an orbitally and spin forbidden 8Big-lAg transition is a possible phosphorescence process [3]. Detailed analyses of the TS absorption of the PBQ crystal and the TS emission of PBQ-h4 in an isotopically mixed crystal predict that the 3Big level is the lowest triplet in the crystal, being located at 18 624 cm-1 separated by about 320 cm-1 (0.04 eV) to lower frequency from the 3Au level. The purpose of this note is to establish the nature of the TS transition in PBQ vapour and to determine the separation between the low-lying n,~ r* triplet states. PBQ-h4,-d4, and toluquinone (TQ) were prepared and purified in the same way as described previously [3]. Argon of 99.9 per cent purity supplied by Seitetsu Chemical Co., Tokyo, and perfluoro-n-hexane obtained from Pierce Chemical Co., Rockford, Illinois, were used without further purification. Light from a 500 W xenon arc was passed through an alcoholic filter solution (5.5 cm optical path) containing 3• 10-5 M ethyl violet and 1• 10-2 M o-nitrotoluene. This was effective for exciting PBQ molecules in only low-lying 1Big and/or 1Au (n,~ r*) states [4]. A horn-shaped cell [5] was used and the emission was photographed on Kodak 103a-F plates with a spectrograph [6] which was mounted normal to the incident light. Exposure time was 100 hours; a slit width of 100/~ m was employed. The phosphorescence spectrum of the PBQ-h4 vapour was observed in three conditions:(a) in the extensively degassed state,(b) and (c) in the presence of argon at about 10 tort and at about 25 torr. The results are shown in figures 1 (a)-(c). Both band location and intensity distribution of the emission in (a) are very similar to those given in a transformer discharge experiment by Jayswal et al.[1, 2] and the band analysis resembles theirs closely except for two bands at 5700 A and 6310 A which should be assigned to 0-1145 (ag) and 0-1145-1675 (ag• ag= Ag), respectively, because of their band spacings and intensities. Thus, we can safely say that the emission consists of only the 3Au-lAg transition in this case. On the other hand, there are several additional bands that appear for the first time in (b) and (c), especially in the latter. Those bands are marked with bold lines in figures 1 (b),(c). If they are assumed to belong to a 3Ble-lAg transition, its origin being located at 18 370 cm-1, the new bands may be assigned
安野俊信：J.Chem.Phys。
DOI：
--
发表时间：
--
期刊：
影响因子：
--
作者：
通讯作者：
--