Ghazy R, Azim S A, Shaheen M, El-Mekawey F
Laser Laboratory, Physics Department, Faculty of Sciences, Tanta University, Tanta, Egypt.
Spectrochim Acta A Mol Biomol Spectrosc. 2004 Jan;60(1-2):187-91. doi: 10.1016/s1386-1425(03)00205-1.
In this paper we used the Stokes shift phenomena to determine the difference in the dipole moments of the excited state micro(e) and ground state micro(g) to be (micro(e)-micro(g)), and the polarizability alpha. In this paper, we studied six different laser dyes belonging to four different classes of laser dyes which are diolefin 2,5-Distyryl pyrazine (DSB); 1,4-Bis (-pyridyl-2-vinyl) benzene (P2VB) and p-Bis-(o-methylstyryl)-benzene (Bis-MSB) with (micro(e)-micro(g)) equal to 6.40, 6.70 and 2.98 Debye, respectively; anthracene class includes 10(4-acetoxyphenyl)-2-methyl-9-acetoxy anthracene (APMAA) with (micro(e)-micro(g)) value of 7.25 Debye; Rhodamine B (RB) with (micro(e)-micro(g)) value of 5.33 Debye; and Coumarin 120 (C120) with the value 3.97 Debye for (micro(e)-micro(g)). In addition the value of both polarizability alpha and the radius r of each investigated laser dye molecule are determined. Therefore, the ratio alpha/r(3) for each dye is calculated to be 0.93, 0.79, 0.39, 0.37, 0.67 and 0.76 for DSP, P2VB, Bis-MSB, APMAA, RB and C120, respectively. The values of r are 4.83, 4.83, 4.90, 5.34, 5.75 and 4.11 A for the above consequence laser dyes. These dyes are studied in a large number of different solvents. The values obtained of (micro(e)-micro(g)) for these selected dyes are positive, which means that the excited state is more polar than the ground state.
在本文中，我们利用斯托克斯位移现象确定激发态μ(e)和基态μ(g)的偶极矩之差为(μ(e)-μ(g))，以及极化率α。在本文中，我们研究了属于四类不同激光染料的六种不同激光染料，它们分别是二烯烃2,5-二苯乙烯基吡嗪(DSB)；1,4-双(-吡啶-2-乙烯基)苯(P2VB)和对双-(邻甲基苯乙烯基)-苯(Bis-MSB)，其(μ(e)-μ(g))分别等于6.40、6.70和2.98德拜；蒽类包括10(4-乙酰氧基苯基)-2-甲基-9-乙酰氧基蒽(APMAA)，其(μ(e)-μ(g))值为7.25德拜；若丹明B(RB)，其(μ(e)-μ(g))值为5.33德拜；以及香豆素120(C120)，其(μ(e)-μ(g))值为3.97德拜。此外，还确定了每种所研究的激光染料分子的极化率α和半径r的值。因此，计算出每种染料的α/r(3)比值，对于DSP、P2VB、Bis-MSB、APMAA、RB和C120分别为0.93、0.79、0.39、0.37、0.67和0.76。上述相应激光染料的r值分别为4.83、4.83、4.90、5.34、5.75和4.11埃。这些染料在大量不同溶剂中进行了研究。这些选定染料的(μ(e)-μ(g))所得值为正，这意味着激发态比基态极性更强。
