Polarization Labeling Spectroscopy Research Articles

Polarization spectroscopy of the E0 g+- B0 u+ band system of Br 2

The E- B (0 g +-0 u +) band system of Br 2 has been investigated at Doppler-limited resolution using polarization labeling spectroscopy. Merged E state data for the three naturally occurring isotopes in the range v E = 0–16, expressed in terms of the constants for 79Br 2, are (in cm −1) Y 0,0 = 49 777.962(54), Y 1,0 = 150.834(22), Y 2,0 = −0.4182(28), Y 3,0 = 6.6(11) × 10 −4, Y 0,1 = 4.1876(28) × 10 −2, Y 1,1 = −1.607(16) × 10 −4, and Y 0,2 = 1.39(39) × 10 −8. The bond distance is r e = 3.194 A ̊ , and the diabatic dissociation energy to Br +( 3P 2) + Br −( 1S 0) is 34 700 cm −1 .

Sequential two-photon spectroscopy of some ion-pair states of IBr

Molecular constants of the first E 0 + ion-pair state of IBr vapor have been determined using polarization-labeling spectroscopy applied to the sequential transitions E 0 + ← B′ 0 + ← X 0 +, while the second f 0 + ion-pair state is reported and characterized for the first time. A least-squares, simultaneous analysis of data for the I 79Br and I 81Br isotopes gives the following constants (in cm −1) for I 79Br: E state: T e = 39487.32(12), ω e = 119.518(21), ω e ξ e = 0.2109(12) , ω e y e = − 2.34(22) × 10 −4, B e = 2.9701(14) × 10 −2 , α e = 5.43(59) × 10 −5, and γ e = − 6.8(16) × 10 −7 . F state: T e = 45382.58(17), ω e = 128.805(66), ω e ξ e = 0.3630(69) , ω e y e = − 9.7(22) × 10 −4, B e = 3.0073(30) × 10 −2, and α e = 8.52(48) × 10 −5 . Preliminary data for the first Ω = 1 ion-pair state, accessed in the sequence 1( 3P 2) ← A( Ω = 1) ← X 0 + , indicate that T e is ≲30 cm −1 higher in energy than that of the E state.

A new ion-pair state of iodine chloride

A previously-unknown ion-pair state of ICl has been identified and characterized in sequential transitions using polarization-labelling spectroscopy. This state is designated 1(3P1), indicating a state of axial electronic angular momentum Ω = 1 correlating diabatically at dissociation with the states I+(3P1) + Cl−(1S0) of the separated ions. The electronic energy and local potential constants for levels with ν = 1–7 are (in cm−1) Tc = 45552.805(23), ωc = 184.854(13), ωcxc = 0.6737(13), Bc = 0.058898(42), and α = 2.485(93) × 10−4, and the equilibrium bond distance is 3.231 Å.

Stimulated Emission from the A1Σ+uBand of Sodium Dimer

Intense stimulated emission from sodium vapor is observed at around 800 nm when it is pumped by a pulsed dye laser around 600 nm. The spectral lines are localized around 800 nm. To investigate the origin of this emission, we try to assign the stimulated lines excited by a dye laser at 632.8 nm (the wavelength of the He-Ne laser) and by a ruby laser at 694.3 nm. Moreover, the A Σ -X Σ transitions at 595.728 and 594.664 nm of a Na 2 which are newly assigned by using the polarization labelling spectroscopy are excited by the output from a cw-dye-laser amplified with N 2 laser-pumped dye amplifier, and some of the stimulated lines are assigned. It is then concluded that the origin of these stimulated emission lines is the A Σ -X Σ transition. Also it can be explained that these stimulated lines come from around the band edge of the A Σ -X Σ transition.

Constants of the second 0 g+ ion-pair state of I 2

The second 0 g + ion-pair state of I 2 is characterized using two-stage polarization-labeling spectroscopy. Molecular constants for this state in the range 0 ≤ v ≤ 25, based on a global leastsquares fit of 450 transitions, are (in cm −1) T e = 47 025.917, ω e = 104.1804, ω e x e = 0.21324, ω e y e = 2.46 × 10 −4, B e = 2.08042 × 10 −2, α e = 5.728 × 10 −5, γ e = 5.8 × 10 −8, and D e = 3.32 × 10 −9. The diabatic potential curve correlates with the states I −( 1S) + I +( 3P 0) of the separated ions.

The E- B band system of diatomic iodine

Sequential pump and probe pulses are used to excite state-selected E ← B ← X transitions in I 2 vapor, and the E ← B bands recorded by polarization-labeling spectroscopy at relatively high dispersion. Molecular constants and Dunham expansion coefficients Y n,0 ( n = 0–7), Y n,1 ( n = 0–3), and Y n,2 ( n = 0, 1) for the E state are obtained in the range 0 ≤ v E ≤ 96, based on a global least-squares fit of 1050 assigned rotational transitions. Definite evidence is cited to show that the EO g + ion-pair state correlates diabatically with the ground state I −( 1S 0) + I +( 3P 2) of the separated ions.

A new ion-pair state of diatomic iodine

Transitions combining the [Formula: see text] state of diatomic iodine with a new ion-pair state designated [Formula: see text] have been observed using Doppler-limited polarization-labelling spectroscopy. A number of vibration – rotation states of [Formula: see text] have been measured and the following vibration and vib-rotational constants determined: Te = 47 027.63(18), ωe = 103.904(18), ωexe = 0.1988(5), Be = 0.020780(14), αe = 5.48(6) × 10−5 and D = 3.5(4) × 10−9cm−1. These constants were derived for f state levels with v = 13 – 25.

Rotational analysis of visible bands of nitrogen dioxide using polarization spectroscopy

Polarization labeling spectroscopy is used to simplify the visible absorption spectrum of NO 2. State-selected spectra of the 2 B 2- 2 A 1 transition in the range 16 600–17 000 and 17 350–17 850 cm −1 are developed using a narrow-band pump operated (1) near 545 nm, where the pumped transitions also belong to the 2 B 2 system, and (2) near 436 nm on a selected transition of the 2 B 1- 2 A 1 (Douglas-Huber) band system. Rotational analyses are given for the K a = 0 and K a = 1 subbands of 11 vibronic bands and limited observations reported for the K a = 0 or 1 manifold of a further 8 bands. Polarization-labeling experiments within the 2 B 1- 2 A 1 band system are also described.

A study of the excited 1Σ +g states in Na 2

Using the technique of two-step polarization labeling spectroscopy seven excited 1Σ + g states in Na 2 have been found. Molecular constants are derived from a Dunham expansion. Tentative assignments are made to the 3p+3p, 3s+ nd and 3s+ ns atomic asymptotes.

Two-step polarization-labeling spectroscopy of excited states ofNa2

Two-step polarization-labeling spectroscopy of diatomic molecules is described. Formulas for relative transition intensities are derived, and their use in determining angular momenta of molecular states is discussed. The experimental apparatus and procedure used to identify twenty-four new $^{1}\ensuremath{\Sigma}_{g}^{+}$, $^{1}\ensuremath{\Pi}_{g}$, and $^{1}\ensuremath{\Delta}_{g}$ states in ${\mathrm{Na}}_{2}$ are described. The states are identified as low-lying members, $n=3 \mathrm{to} 14$, of several molecular Rydberg series, and the dependence of their properties on principal quantum numbers is shown. These results are extrapolated to yield constants for the ground state of $\mathrm{Na}_{2}^{}{}_{}{}^{+}$.

Polarization labelling spectroscopy of the A 1Σ +u band of Na 2

A result of the polarization labelling spectroscopy of the A 1Σ + u band of sodium dimer for the high vibrational quantum number υ'>20 is reported. The frequency difference δ v= v obs- v cal is found to decrease from 2 to -3 cm -1 as the rotational levels (υ'=27−30), where v cal is the calculated transition frequency using the Dunham coefficients of Demtröder and Stock for the X 1Σ + g band and of Kusch and Hessel for the A 1Σ + u band.

Polarization labeling spectroscopy of NO 2

Polarization-labeling spectroscopy is used to simplify the visible spectrum of nitrogen dioxide. Nonlinear polarization effects are used to label and probe molecules in selected rotational-vibrational levels. Those labeled molecules can be detected by their depolarizing effect on a probe laser. The resulting spectra are considerably less complicated than normal absorption spectra. P- and R-branch transitions can be readily identified, and approximate excited-state rotational constants are determined. With more powerful lasers, it may be possible to use polarization labeling to unravel the very complicated vibrational structure of the NO 2 excited states.