Dye Laser Excitation Spectroscopy Research Articles

The C–C–H Bending Vibration Mode (ν4) in the Electronic Ã2Π and X2Σ+ States of the CaCCH Radical

The first excited C–C–H bending vibration levels in the CaCCH Ã2Π and X2Σ+ states have been rotationally analyzed through cw dye laser excitation spectroscopy of the band. The upper state is subject to Renner–Teller and spin–orbit splittings. Strong K-type resonance interactions were observed between the nearby 2Δ and 2Σ vibronic components. A total of 667 rotational lines were recorded with high precision and fitted to a model involving a full matrix treatment of the interactions. The Renner–Teller parameter has been determined as ϵ4ω4 = 1.85(4) cm−1.

Laser and Fourier Transform Spectroscopy of the [23.8]1-X0+ System of ReN

The emission spectrum of ReN has been observed in the 400-476 nm spectral region using a Fourier transform spectrometer. The bands were excited in a rhenium hollow cathode lamp in the presence of a trace of N2. The observed bands, with the 0-0 band at 23 746.42 cm−1, have been assigned as the [23.8]1-X0+ electronic transition. A rotational analysis of the 0-1, 0-0, and 1-0 bands for both 187ReN and 185ReN isotopomers has been performed. The principal ground state equilibrium molecular constants for 187ReN obtained from this analysis are B′′e = 0.482414(11) cm−1, r″e = 1.63780(2) Å, while the corresponding excited state values are B′e = 0.441093(13) cm−1, r′e = 1.71280(3) Å. The 0-0 band was also observed by pulsed dye laser excitation spectroscopy using a free jet expansion source. In this experiment, the ReN was made by laser vaporization of a rhenium rod followed by reaction with NH3. The excited [23.8]1 state has a fluorescence lifetime of 201 ± 1 nsec. There are no previously reported observations of the ReN molecule.

A laser study of the blue electronic transitions of CaS

Three new electronic transitions of CaS have been observed in the blue region of the spectrum. The vibrational bands in these transitions span thousands of cm−1 owing to a large change in geometry. Approximately 1000 cm−1 portion of the spectrum containing these bands has been recorded at high resolution by dye laser excitation spectroscopy and analyzed. The new states all have Ω=1, and are tentatively labeled G 1Π, F 1Π, and f 3Π1. Spectroscopic constants have been generated for all three upper states and for the X 1Σ+ state from a fit to 4340 individual lines. These constants have been used to generate potential curves and Franck–Condon factors.

The [formula omitted] transition of CaOD

The B ̃ 2 Σ + - X ̃ 2 Σ + transition of CaOD near 5550 Å was studied using dye laser excitation spectroscopy. The 000-000 band was rotationally analyzed and r 0 structures were established for both states. For the B ̃ 2 Σ + state the following bond lengths were found: r CaO = 1.9697 A ̊ and r OH = 0.9179 A ̊ , while for the X ̃ 2 Σ + state r CaO = 1.9849 A ̊ and r OH = 0.9207 A ̊ .

7F 0 → 5D 0 excitation spectrum of Cs 2NaEuCl 6 and Cs 2NaY 1− xEu xCl 6

The 7F 0 → 5D 0 transition of EuCl 6 3− in cubic environments in the title compounds has been studied by dye laser excitation spectroscopy. Structured vibronic origins due to the ν 4, ν 3 and the sodium lattice vibrations dominate the vibronic spectrum. Vibrational dispersion of ν 4 and ν 3 is surprisingly large at about 30 and 70 cm −1, respectively. The intensity of the sodium motion is much higher than for other 7F J ↔ 5D J transitions. These observations are important in understanding energy migration in the title compounds.

Zero-phonon lines and energy transfer between chromium(III) and neodymium(III) multisites in yttrium aluminium garnet (YAG)

Energy-transfer processes between Cr 3+ and Nd 3+ multisites in YAG have been studied. 4A 2→ 4T 2 zero-phonon and 4A 2→ 2T 1 transitions of Cr 3+ were observed by high-resolution dye laser excitation spectroscopy.

Rotational analysis of the [formula omitted] transition of calcium monoacetylide, CaCCH

The 0-0 band of the A ̃ 2 Π- X ̃ 2 Σ + transition of the CaCCH molecule was rotationally analyzed by dye laser excitation spectroscopy with narrow band fluorescence detection. The rotational constants extracted from the line positions enabled us to estimate the Ca-C bondlength to be 2.25 Å in the ground electronic state. This work represents the first high-resolution analysis of a metal acetylide molecule.

Dye laser excitation spectroscopy of the 3-3 band in the B3Π(0 +)← X1Σ + transition of BrF

Dye laser excitation spectroscopy of the 3-3 band in the B3Π(0 +)← X1Σ + transition of BrF

Dye laser excitation spectroscopy of two new bands of the DSO radical in 6100-Å region

Two new bands of the DSO radical are studied by Doppler-limited dye laser excitation spectroscopy. The observed lines in both of the bands are assigned and analyzed to determine molecular constants for each of the excited states. The band origins of the two bands are 16 281.5550(2.5σ = 0.0014) cm −1 and 16 536.1666(2.5σ = 0.0015) cm −1. A force field analysis in the A ̃ 2A′ state is made by using available fundamental frequencies and inertia defects. This leads to a revision of the vibronic assignment for the band studied previously (N. Ohashi, M. Kakimoto, S. Saito, and E. Hirota, J. Mol. Spectrosc. 84, 204–224 (1980)); this band observed at 16 413.8740(20) cm −1 is reassigned to A ̃ 2A′(012) ← X ̃ 2A″(000) , whereas two new bands detected at 16 281.5550(14) and 16 536.1666(15) cm −1 are interpreted as A ̃ 2A′(021) ← X ̃ 2A″(000) and A ̃ 2A′(003) ← X ̃ 2A″(000) , respectively. An additional support for the present assignment is obtained by calculating the Franck-Condon factor.

Doppler-limited dye laser excitation spectroscopy of the 4 01 band of the [formula omitted] system of D 2CS

The 4 0 1 vibronic band of the A ̃ 1A 2- X ̃ 1A 1 electronic system of D 2CS was observed between 16 620 and 16 837 cm −1 with Doppler-limited resolution using cw dye laser excitation spectroscopy. More than 2400 transitions have been assigned, permitting a refinement of the molecular constants in the excited state. Combination relations from the extensive data set together with published microwave frequencies have also resulted in refined ground state constants. Very few local perturbations were observed. The molecular constants determined reproduce the observed transition frequencies with an average deviation of 0.005 cm −1.

Observations on the B1Π state of the NaK molecule

The lowest 1Π state of the NaK molecule, B(1) 1Π, which dissociates to Na (2S1/2) + K (2P3/2), has been studied in three ways: (i) by laser-induced fluorescence recorded at high resolution by Fourier-transform spectrometry, (ii) by dye-laser excitation spectroscopy, and (iii) by observations of the effect of an electric field, which mixes the e and f parity levels of the B1Π state. The B state is subject to numerous small perturbations, many of which arise from interactions with a triplet state, c3Σ+, and these interactions modify the extent of e–f mixing and thus the relative intensities of R and P lines on one hand and the Q lines on the other. These observations of the Stark effect enable perturbation maxima to be located and thus allow relatively unperturbed energy levels to be identified. Constants from these levels of B1Π have been determined from a weighted least squares fit to 1776 lines of the B1Π – X1Σ+ transition as follows:[Formula: see text]

Characterization of lanthanide (III) ion binding to calmodulin using luminescence spectroscopy.

Pulsed dye laser excitation spectroscopy of the 7F0----5D0 transition of Eu(III) reveals only a single peak as this ion is titrated into apocalmodulin. A titration based on the intensity of this transition shows that the first two Eu(III) ions bind quantitatively to two tight sites, followed by weaker binding (Kd = 2 microM) to two additional sites under conditions of high ionic strength (0.5 M KC1). This excitation experiment is also shown to be a general method for measuring contaminating levels of EDTA down to 0.2 microM in proton solutions. Experiments with Tb(III) using both direct laser excitation and indirect sensitization of Tb(III) luminescence through tyrosine residues in calmodulin also give evidence for two tight and two weaker binding sites (Kd = 2-3 microM). The indirect sensitization results primarily upon binding to the two weaker sites, implying that Tb(III) binds first to domains I and II, which are remote from tyrosine-containing domains III and IV. The 7F0----5D0 excitation signal of Eu(III) was used to measure the relative overall affinities of the tripositive lanthanide ions, Ln(III), across the series. Ln(III) ions at the end of the series are found to bind more weakly than those at the beginning and middle of the series. Eu(III) excited-state lifetime measurements in H2O and D2O reveal that two water molecules are coordinated to the Eu(III) at each of the four metal ion binding sites. Measurements of Förster-type nonradiative energy-transfer efficiencies between Eu(III) and Nd(III) in the two tight sites were carried out by monitoring the excited-state lifetimes of Eu(III) in the presence and absence of the energy acceptor ion Nd(III).(ABSTRACT TRUNCATED AT 250 WORDS)

Doppler-limited dye laser excitation spectroscopy of the à 1A′′(000)–X̃ 1A′(000) band of HSiF

The à 1A′′(000)–X̃ 1A′(000) band of HSiF was observed by Doppler-limited dye laser excitation spectroscopy. The HSiF molecule was produced by the reaction of SiH3F with microwave discharge products of CF4. The observed spectrum was found to be almost free of perturbations and was readily assigned to about 1300 transitions of K′a−K′′a=5–6, 4–5, 3–4, 2–3, 1–2, 0–1, 1–0, 2–1, 3–2, 4–3, 5–4, 0–0, 1–1, and 2–0. A least-squares analysis of the observed spectrum yielded the rotational constants and the centrifugal distortion constants for both the à and X̃ states. The molecular structure was discussed using the observed rotational constants.

Doppler-limited dye laser excitation spectroscopy of DNO: Predissociation of DNO

The cw dye laser excitation spectrum of the (110)-(000) and (021)-(000) vibronic bands of the A ̃ 1A″- X ̃ 1A′ system of DNO was observed between 16530 and 16860 cm −1 with Doppler-limited resolution. A rotational analysis of the two bands gave values for the rotational constants and centrifugal distortion constants. DNO was produced by the pyrolysis method and more than 1200 lines were observed in the two bands. A total of 1112 of these lines could be assigned to 9 and 11 subbands of the (110)-(000) and (021)-(000) bands, respectively. The molecular constants determined reproduce the observed transition frequencies with an average deviation of 0.011 and 0.008 cm −1, respectively. Extensive perturbations in the excited state were found in most of the subbands. “Extra” lines were observed in connection with several of these perturbations. Accurate determination of the dissociation energy has been obtained; D 0 = 17010 ± 10 cm −1.

Dye laser excitation spectroscopy of the CCN radical: The [formula omitted] and (0,2,0)-(0,2,0) bands

The two hot bands of the A ̃ 2 Δ i- X ̃ 2 Π r electronic transition of the CCN radical were observed by cw dye laser excitation spectroscopy with Doppler-limited resolution. From an analysis of the observed spectrum, the rotational, centrifugal distortion, and spin-orbit and spin-rotation coupling constants were determined for the (0,1,0) 2Δ, (0,1,0) μ 2Σ, and (0,2,0) 2Φ levels in the ground electronic state and for the (0,1,0) 2Φ, (0,1,0) 2Π, and (0,2,0) 2Γ levels in the excited electronic state. The rotational constant in X ̃ (0,1,0) 2 Δ was found to be considerably different from that of X ̃ (0,1,0)μ 2 Σ , and the difference was explained by the rovibronic interaction including the Renner effect. The two anharmonic potential constants W 1,3 and W 2,3 were calculated from the rotational constant differences.

Dye laser spectroscopy of the B 2 Σ + -X 2Σ + transition of CaOH

The B 2Σ +-X 2Σ + transition of CaOH has been examined by the technique of dye laser excitation spectroscopy. The rotational structure of the 000-000 and 100-100 bands was determined.

Doppler-limited dye laser excitation spectroscopy of HCCl

The cw dye laser excitation spectrum of the A ̃ 1A″(050) ← X ̃ 1A′(000) vibronic band of HCCl was observed between 16 539 and 16 656 cm −1 with the Doppler-limited resolution, 0.03 cm −1. The HCCl molecule was generated by the reaction of discharged CF 4 with CH 3Cl. The observed spectra were assigned to c-type transitions with Δ K a = ±1 and also to axis-switching transitions with Δ K a = 0 or −2, but all with K′ a = 0, both for HC 35Cl and HC 37Cl. A rotational analysis yielded the rotational constants and quartic centrifugal distortion constants for the ground vibronic state and the band origin. A weak vibronic band, about one-third as intense as the main band, was found at about 57 cm −1 to the violet of the main band for both isotopic species, and was ascribed to a transition from the ground vibronic state to a vibrational level, possibly (041), of the à state. The rotational levels of HC 35Cl in the à state showed a large perturbation; the J′ = 8, 9, and 10 levels were found to be split into two components. A normal coordinate analysis was carried out to calculate the centrifugal distortion constants and the inertia defect, which were in fair agreement with the observed values. The molecular structure of HCCl in the ground vibronic state was recalculated from the rotational constants of the two isotopic species combined with the 0.75 B 0 + 0.25 C 0 value previously reported for DC 35Cl.

Doppler-limited dye laser excitation spectroscopy of the CCN radical

The cw dye laser excitation spectrum of the A ̃ 2 Δ(000) ← X ̃ 2 Π(000) vibronic transition of the CCN radical was observed between 21 205 and 21 335 cm −1 with the Doppler-limited resolution, 0.04 cm −1. The CCN radical was produced by reaction of microwave discharged CF 4 with CH 3CN. The observed spectrum was analyzed to determine rotational and centrifugal constants and effective spin-orbit and spin-rotation coupling constants for both the A ̃ 2 Δ(000) and the X ̃ 2 Π(000) states, and also the Λ-type doubling constants for the X ̃ 2 Π(000) state. The constants determined reproduce the observed spectrum with an average deviation of 0.0027 cm −1, and are considered to be precise enough for predicting the ground-state microwave transition frequencies. No evidence was found for perturbation in either the A ̃ 2 Δ(000) or the X ̃ 2 Π(000) state.

ChemInform Abstract: DOPPLER‐LIMITED DYE LASER EXCITATION SPECTROSCOPY OF MONOFLUOROMETHYLENE‐D

Chemischer InformationsdienstVolume 13, Issue 16 Physical Organic Chemistry ChemInform Abstract: DOPPLER-LIMITED DYE LASER EXCITATION SPECTROSCOPY OF MONOFLUOROMETHYLENE-D T. SUZUKI, T. SUZUKISearch for more papers by this authorS. SAITO, S. SAITOSearch for more papers by this authorE. HIROTA, E. HIROTASearch for more papers by this author T. SUZUKI, T. SUZUKISearch for more papers by this authorS. SAITO, S. SAITOSearch for more papers by this authorE. HIROTA, E. HIROTASearch for more papers by this author First published: April 20, 1982 https://doi.org/10.1002/chin.198216048AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume13, Issue16April 20, 1982 RelatedInformation

Doppler-limited dye laser excitation spectroscopy of DCF

The dye laser excitation spectrum of the A ̃ 1A″(000)- X ̃ 1A′(000) vibronic transition of DCF was observed between 17 200 and 17 400 cm −1 with the Doppler-limited resolution. DCF was produced by the reaction of microwave-discharged CF 4 with CD 3F. The observed spectra, which were found to be nearly free of perturbations, were assigned to 858 transitions of the K′ a − K″ a = 4−5, 3−4, 2−3, 1−2, 0−1, 1−0, 2−1, 3−2, 3−3, 2−2, 1−1, 0−0, 2−0, and 0−2 subbands, and were analyzed to determine the rotational constants and centrifugal distortion constants for both the X ̃ and A ̃ states. The rotational constants of DCF thus determined were combined with those of HCF to calculate the structural parameters for this molecule: r( CH) = 1.138 A ̊ , r( CF) = 1.305 A ̊ , and ∠HCF = 104.1° for the ground X ̃ state, and r( CH) = 1.063 A ̊ , r( CF) = 1.308 A ̊ , and ∠HCF = 123.8° for the excited A ̃ state.