The determination of the infrared radiative lifetimes of a vibrationally excited neutral molecule using stimulated-emission-pumping, molecular-beam time-of-flight

Drabbels, Marcel; Wodtke, Alec M.

doi:10.1063/1.473047

Cited by 33 publications

(21 citation statements)

References 32 publications

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“…8 the square of the transition dipole moment for the sixth overtone is compared with other transitions originating in Љ= 0, and with high-transitions measured by Drabbels and Wodtke. 16 Concentrating on the first seven data points ͑originating in Љ=0͒, there is a significant curvature in the plot due to electrical and mechanical anharmonicities at higher vibrational levels. It is also interesting to compare the Herman-Wallis factor for the sixth overtone with other overtones originating in Љ= 0, as shown in Fig.…”

Section: B Resultsmentioning

confidence: 98%

Measurement of the sixth overtone band of nitric oxide, and its dipole moment function, using cavity-enhanced frequency modulation spectroscopy

Bood

McIlroy

Osborn

2006

The Journal of Chemical Physics

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We applied cavity-enhanced frequency modulation absorption spectroscopy (also known as noise-immune cavity-enhanced optical heterodyne molecular spectroscopy) to perform high-resolution spectroscopy of the sixth overtone band of nitric oxide near 797 nm. By using novel high-bandwidth balanced detectors, baseline variations caused by residual amplitude modulation were significantly reduced. The ultrahigh sensitivity (2 x 10(-10) cm(-1) minimum detectable absorption at 1 Hz detection bandwidth) of our spectrometer allowed accurate measurements of 15 individual line intensities of P- and R-branch transitions in the 2Pi(1/2)-2Pi(1/2) subband. A vibrational transition moment of 3.09(6) muD+/-13% and Herman-Wallis coefficients of a = -0.0078(26) and b = 0.001 25(45) were found by fitting the line intensities. Based on our measured transition moment, and those of other transitions from the literature, a new parametrization for the electric dipole moment function (EDMF) of nitric oxide, valid for 0.91 < or = r < or = 1.74 A, has been extracted. The residuals of this fit demonstrate that the derived EDMF is the most accurate representation to date of the dipole moment function. The new EDMF will be valuable for accurate intensity prediction of transitions that cannot be easily measured experimentally.

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Section: B Resultsmentioning

confidence: 98%

Measurement of the sixth overtone band of nitric oxide, and its dipole moment function, using cavity-enhanced frequency modulation spectroscopy

Bood

McIlroy

Osborn

2006

The Journal of Chemical Physics

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“…10,18 By comparison, photon emission from NO(n ¼ 15) is dominated by Dn $ À1 transitions. 27 These results demonstrate a crucial difference between electron mediated and photon mediated vibrational transitions; namely, the probability of ''high overtone'' transitions can be much larger in the former than in the latter. This begs the question to what extent electron mediated processes might be used to circumvent optical selection rules for vibrational overtone excitation, providing an avenue for direct pumping of many quanta into molecular vibration on the sub ps time-scale.…”

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confidence: 80%

Vibrational overtone excitation in electron mediated energy transfer at metal surfaces

Cooper

Rahinov

et al. 2010

Chem. Sci.

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Vibrational overtone excitation is, in general, inefficiently stimulated by photons, but can under some circumstances be efficiently stimulated by electrons. Here, we demonstrate electron mediated vibrational overtone excitation in molecular collisions with a metal surface. Specifically, we report absolute vibrational excitation probabilities to n ¼ 1 and 2 for collisions of NO(n ¼ 0) with a Au(111) surface as a function of surface temperature from 300 to 985 K. In all cases, the observed populations of vibrationally excited NO are near those expected for complete thermalization with the surface, despite the fact that the scattering occurs through a direct ''single bounce'' mechanism of sub-ps duration. We present a state-to-state kinetic model, which accurately describes the case of near complete thermalization (a regime we call the strong coupling case) and use this model to extract state-to-state rate constants. This analysis unambiguously shows that direct vibrational overtone excitation dominates the production of n ¼ 2 and that, within the context of our model, the intrinsic strength of the overtone transition is of the same order as the single quantum transition, suggesting a possible way to circumvent optical selection rules in vibrational pumping of molecules. This result also suggests that previous measurements of vibrational relaxation of highly vibrationally excited NO exhibiting highly efficient multi-quantum jumps (Dn $ À8) are mechanistically similar to vibrational excitation of NO(n ¼ 0).

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“…No informa- tion on the population in the Jϭ1.5 level of vϭ19 could be obtained since this state is also populated by spontaneous infrared emission from vϭ20. 19 Process ͑1͒ could be observed for vϭ20, 21, and 22, where the energy defect is Ϫ49, Ϫ18, and ϩ14 cm Ϫ1 , respectively. 20,21 Here a positive number indicates endoergicity, whereas a negative number indicates exoergicity.…”

Section: Resultsmentioning

confidence: 90%

“…When delayed, collisions between the prepared NO molecules and N 2 O are not possible and any apparent population transfer from the prepared state of NO results from collisions with background gas or infrared emission. 16,19 The difference between odd and even shots is recorded using the boxcar average in ''toggle mode'' to distinguish the desired signal. Typically, this procedure has been repeated for 5-10 scans to yield data with an error of ϳ15%.…”

Section: Methodsmentioning

confidence: 99%

Rotational motion compensates the energy defect in near-resonant vibration–vibration energy transfer: A state-to-state study of NO(v)+N2O

Drabbels

Wodtke

1998

The Journal of Chemical Physics

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Our lack of understanding of the factors that compensate energy defects in near resonant V-V energy transfer constrains our ability to accurately predict resonance widths and, thus, the overall importance of such processes. We have carried out one of the first truly state-to-state measurements of near resonant V-V energy transfer under single collision conditions, employing the crossed molecular beams, stimulated emission pumping technique. We have varied the energy defect ⌬E for the process: NO X 2 ⌸(v)ϩN 2 O(0,0,0)→NO X 2 ⌸(vϪ1)ϩN 2 O(0,0,1), by changing the prepared vibrational state from vϭ22 (⌬Eϭϩ14 cm Ϫ1 ) to vϭ21 (⌬EϭϪ18 cm Ϫ1 ) to vϭ20 (⌬EϭϪ49 cm Ϫ1 ). Changes in the energy transfer efficiencies and rotational distributions of vibrationally inelastically scattered NO with energy defect both strongly suggest that molecular rotation ͑both of NO and N 2 O͒ is responsible for compensating the energy defect. Furthermore it appears that relative translation is ineffective in compensating the energy defect. A ⌬J NO ϳ⌬J N 2 0 approximation also appears valid.

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The determination of the infrared radiative lifetimes of a vibrationally excited neutral molecule using stimulated-emission-pumping, molecular-beam time-of-flight

Cited by 33 publications

References 32 publications

Measurement of the sixth overtone band of nitric oxide, and its dipole moment function, using cavity-enhanced frequency modulation spectroscopy

Measurement of the sixth overtone band of nitric oxide, and its dipole moment function, using cavity-enhanced frequency modulation spectroscopy

Vibrational overtone excitation in electron mediated energy transfer at metal surfaces

Rotational motion compensates the energy defect in near-resonant vibration–vibration energy transfer: A state-to-state study of NO(v)+N2O

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