Determination of rotational constants in a molecule by femtosecond four-wave mixing

Frey, Hans‐Martin; Beaud, P.; Gerber, T.; Mischler, B.; Radi, P. P.; Tzannis, Alexios-Paul

doi:10.1002/(sici)1097-4555(200001/02)31:1/2<71::aid-jrs496>3.0.co;2-d

Cited by 39 publications

(4 citation statements)

References 17 publications

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“…6-8,13,14,17-20, [25][26][27][28][29][30][31][32][33][34][35] In off-resonant four-wave mixing -which is appropriate here, since p-DFB is com-pletely transparent at the 800 nm laser wavelength -the DFWM signal of the gas sample is proportional to the square modulus of its time-dependent third-order susceptibility, [36][37][38] χ (3) (t), which can be written as…”

Section: A Modeling the Degenerate Four-wave Mixing Signalmentioning

confidence: 99%

Rotational constants and structure of para-difluorobenzene determined by femtosecond Raman coherence spectroscopy: A new transient type

Den

Frey

Felker

et al. 2015

The Journal of Chemical Physics

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Articles you may be interested inAccurate rotational constant and bond lengths of hexafluorobenzene by femtosecond rotational Raman coherence spectroscopy and ab initio calculations J. Chem. Phys. 141, 194303 (2014) Femtosecond Raman rotational coherence spectroscopy (RCS) detected by degenerate four-wave mixing is a background-free method that allows to determine accurate gas-phase rotational constants of non-polar molecules. Raman RCS has so far mostly been applied to the regular coherence patterns of symmetric-top molecules, while its application to nonpolar asymmetric tops has been hampered by the large number of RCS transient types, the resulting variability of the RCS patterns, and the 10 3 -10 4 times larger computational effort to simulate and fit rotational Raman RCS transients. We present the rotational Raman RCS spectra of the nonpolar asymmetric top 1,4-difluorobenzene (para-difluorobenzene, p-DFB) measured in a pulsed Ar supersonic jet and in a gas cell over delay times up to ∼2.5 ns. p-DFB exhibits rotational Raman transitions with ∆J = 0, 1, 2 and ∆K = 0, 2, leading to the observation of J−, K−, A−, and C-type transients, as well as a novel transient (S-type) that has not been characterized so far. The jet and gas cell RCS measurements were fully analyzed and yield the ground-state (v = 0) rotational constants A 0 = 5637.68(20) MHz, B 0 = 1428.23(37) MHz, and C 0 = 1138.90(48) MHz (1σ uncertainties). Combining the A 0 , B 0 , and C 0 constants with coupled-cluster with single-, double-and perturbatively corrected triple-excitation calculations using large basis sets allows to determine the semi-experimental equilibrium bond lengths r e (C 1 -C 2 ) = 1.3849(4) Å, r e (C 2 -C 3 ) = 1.3917(4) Å, r e (C-F) = 1.3422(3) Å, and r e (C 2 -H 2 ) = 1.0791(5) Å. C 2015 AIP Publishing LLC. [http://dx

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Section: A Modeling the Degenerate Four-wave Mixing Signalmentioning

confidence: 99%

Rotational constants and structure of para-difluorobenzene determined by femtosecond Raman coherence spectroscopy: A new transient type

Den

Frey

Felker

et al. 2015

The Journal of Chemical Physics

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“…Cooling the sample in a supersonic jet strongly reduces the vibrational and rotational temperatures, and the comparison with room-temperature RCS spectra , allows one to observe the coupling of the pseudorotational and the ν 23 radial vibrations to the rotational constants. The adiabatic jet expansion also increases the time between collisions beyond the experimental time scale of ∼5 ns, effectively eliminating the J - and M J -dephasing collisions that lead to a loss of RCS signal. ,,, …”

Section: Introductionmentioning

confidence: 99%

“…Rotational coherence spectroscopy (RCS) is a time-domain spectroscopic method, − which, unlike microwave and millimeter-wave spectroscopic methods, , can also be applied to nonpolar molecules. − We have shown for several nonpolar linear and symmetric tops such as CS 2 , cyclopropane to cyclohexane, cyclooctatetraene, 1,3,5-trifluorobenzene, and hexafluorobenzene that the rotational constants can be determined with a relative accuracy of ∼10 –6 if the RCS signal contributions from low-lying thermally populated excited vibrations are taken into account. − We have also determined semiexperimental equilibrium ( r e ) C–C and C–F bond lengths in the above molecules.…”

Section: Introductionmentioning

confidence: 99%

Probing the Structure, Pseudorotation, and Radial Vibrations of Cyclopentane by Femtosecond Rotational Raman Coherence Spectroscopy

et al. 2015

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The 10 nJ pulses from a Kerr-lens mode-locked Ti:sapphire oscillator (Mai Tai, SpectraPhysics) are amplified in a Ti:sapphire multipass chirped-pulse amplifier system (ODIN DQC, Quantronix), which is pumped by a 14 W pulsed frequency- The output of the fs laser system is reduced to a laser pulse energy between 75 − 120 µJ and split into three equally intense pump, dump and probe beams, which are aligned in a forward BOXCARS degenerate four-wave mixing (DFWM) arrangement, and focused by an f = 1000 mm achromatic lens into the center of either a 1.0 m long stainless-steel gas-cell or into the supersonic jet vacuum chamber. The probe beam runs over a retroreflector that is mounted on a high-precision 1000 mm long delay stage, housed in a vacuum tank with 800 nm AR coated windows that is evacuated to < 10 −3 mbar. The time-delay of the probe pulse is by measuring the retroreflector displacement with a two-axis He-Ne laser interferometric system (SP2000 D; SIOS GmbH) with an accuracy of ±30 nm. After the output window of gas-cell or jet vacuum chamber, the three input beams are blocked by a mask, while the DFWM signal beam is collimated, spatially filtered and detected by a thermoelectrically cooled GaAs photomultiplier (H7422-50, Hamamatsu). The signals are recorded with a 1 GHz/8-bit oscilloscope at a sweep rate of 8 GHz/s. The experiment is controlled and the data acquired by a PC using LabView.

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“…Femtosecond DFWM can probe the rotational constant B, the centrifugal term D J , the temperature and higher distortion terms of the molecule [18]. The accuracy is better than 10 −4 for rotational constants.…”

Section: Dfwmmentioning

confidence: 99%

Femtosecond Raman time-resolved molecular spectroscopy

Lavorel

Tran

Hertz

et al. 2004

Comptes Rendus. Physique

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The applicability of several femtosecond time resolved non-linear coherent techniques such as Raman induced polarization spectroscopy (RIPS), degenerate four-wave mixing (DFWM) and coherent anti-Stokes Raman spectroscopy (CARS) for molecular spectroscopy is presented. All methods rely on the initial coherent excitation of molecular states producing wavepackets, whose time evolution is then measured. In the case of RIPS and DFWM only pure rotational transitions are involved, whereas in CARS vibrational states can be excited. First the methodology of concentration and temperature measurements using RIPS in gas mixtures involving N 2 , CO 2 , O 2 , and N 2 O is shown. In addition some applications are given for the two closely related techniques DFWM and CARS. DFWM is suitable to extract the rotational constants of molecules to a high accuracy as is demonstrated by measurements on CO 2 and pyrimidine, which is a biological building block. CARS can be used to study higher order molecular constants and to sensitively determine temperature in, e.g., H 2 up to 2000 K. Finally, CARS is applied for the investigation of pressure dependent lineshape models, which are important for the temperature evaluation from spectroscopic data.

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Determination of rotational constants in a molecule by femtosecond four-wave mixing

Cited by 39 publications

References 17 publications

Rotational constants and structure of para-difluorobenzene determined by femtosecond Raman coherence spectroscopy: A new transient type

Rotational constants and structure of para-difluorobenzene determined by femtosecond Raman coherence spectroscopy: A new transient type

Probing the Structure, Pseudorotation, and Radial Vibrations of Cyclopentane by Femtosecond Rotational Raman Coherence Spectroscopy

Femtosecond Raman time-resolved molecular spectroscopy

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