Sweeney S J, Ahmed E H, Qi P, Kirova T, Lyyra A M, Huennekens J
Department of Physics, Lehigh University, 16 Memorial Drive East, Bethlehem, Pennsylvania 18015, USA.
J Chem Phys. 2008 Oct 21;129(15):154303. doi: 10.1063/1.2982780.
We describe a two-laser experiment using optical-optical double resonance fluorescence and Autler-Townes (AT) splittings to determine the NaK 3 (1)Pi-->1(X)(1)Sigma(+), 2(A)(1)Sigma(+) absolute transition dipole moment functions. Resolved 3 (1)Pi-->A (1)Sigma(+) and 3 (1)Pi-->X (1)Sigma(+) fluorescence was recorded with the frequencies of a titanium-sapphire laser (L1) and a ring dye laser (L2) fixed to excite particular 3 (1)Pi(upsilon = 19,J = 11,f)<--A (1)Sigma(+)(upsilon('),J(') = J = 11,e)<--X (1)Sigma(+)(upsilon("),J(") = J(')+/-1,e) double resonance transitions. The coefficients of a trial transition dipole moment function mu(e)(R) = a(0)+a(1)(R(eq)/R)(2)+a(2)(R(eq)/R)(4)+... were adjusted to match the relative intensities of resolved spectral lines terminating on the lower A (1)Sigma(+)(upsilon('),11,e) and X (1)Sigma(+)(upsilon("),11,e) levels. These data provide a relative measure of the functions mu(e)(R) over a broad range of R. Next, L2 was tuned to either the 3 (1)Pi(19,11,f)<--A (1)Sigma(+)(10,11,e) or 3 (1)Pi(19,11,f)<--A (1)Sigma(+)(9,11,e) transition and focused to an intensity large enough to split the levels via the AT effect. L1 was scanned over the A (1)Sigma(+)(10,11,e)<--X (1)Sigma(+)(1,10,e) or A (1)Sigma(+)(9,11,e)<--X (1)Sigma(+)(0,12,e) transition to probe the AT line shape, which was fit using density matrix equations to yield an absolute value for mu(ik) = integral psi(vib) (i)(R)mu(e)(R)psi(vib)(k)(R)dR, where i and k represent the upper and lower levels, respectively, of the coupling laser (L2) transition. Finally, the values of mu(ik) were used to place the relative mu(e)(R) functions obtained with resolved fluorescence onto an absolute scale. We compare our experimental transition dipole moment functions to the theoretical work of Magnier et al. [J. Mol. Spectrosc. 200, 96 (2000)].
我们描述了一个双激光实验，该实验利用光 - 光双共振荧光和奥特勒 - 陶尼斯（AT）分裂来确定NaK的3 (1)Pi→1(X)(1)Sigma(+)、2(A)(1)Sigma(+)绝对跃迁偶极矩函数。通过固定钛宝石激光器（L1）和环形染料激光器（L2）的频率来记录分辨的3 (1)Pi→A (1)Sigma(+)和3 (1)Pi→X (1)Sigma(+)荧光，以激发特定的3 (1)Pi(υ = 19,J = 11,f)←A (1)Sigma(+)(υ',J' = J = 11,e)←X (1)Sigma(+)(υ",J" = J'+/-1,e)双共振跃迁。调整试探性跃迁偶极矩函数μe(R) = a0 + a1(Req/R)2 + a2(Req/R)4 +...的系数，以匹配终止于较低A (1)Sigma(+)(υ',11,e)和X (1)Sigma(+)(υ",11,e)能级的分辨谱线的相对强度。这些数据提供了在广泛的R范围内μe(R)函数的相对测量值。接下来，将L2调谐到3 (1)Pi(19,11,f)←A (1)Sigma(+)(10,11,e)或3 (1)Pi(19,11,f)←A (1)Sigma(+)(9,11,e)跃迁，并聚焦到足够大的强度以通过AT效应分裂能级。扫描L1通过A (1)Sigma(+)(10,11,e)←X (1)Sigma(+)(1,10,e)或A (1)Sigma(+)(9,11,e)←X (1)Sigma(+)(0,12,e)跃迁来探测AT线形，使用密度矩阵方程对其进行拟合，以得到μik = ∫ψ(vib)i(R)μe(R)ψ(vib)k(R)dR的绝对值，其中i和k分别代表耦合激光器（L2）跃迁的上能级和下能级。最后，使用μik的值将通过分辨荧光获得的相对μe(R)函数置于绝对尺度上。我们将我们的实验跃迁偶极矩函数与Magnier等人的理论工作[《分子光谱学杂志》200, 96 (2000)]进行比较。
