The vibrational structure of NO+(X 1Σ+) from charge-exchange mass spectrometry

Charge-exchange mass spectrometry has been used to detect the first five vibrationl levels of the electronic ground-state ion NO^?(X ¹Σ^?). The absolute charge-exchange cross sections between thermal NO gas and 33 positive ions of 10 eV kinetic energy are given.     

Molecular structure of 8-carboxy-18-chloro-14-hydroxy-20-isopropyl-16-methoxy-4,8-dimethyl-15-oxaoctacyclo-[11.7.1.03,1204,9012,19014,18016,21017,20]henicosane

The structure of 8-carboxy-18-chloro-14-hydroxy-20-isopropyl-16-methoxy-4,8-dimethyl-15-oxaoctacyclo[11.7.1.0^3,120^4,90^12,190^14,180^16,210^17,20]henicosane has been determined by single crystal X-ray diffraction. Original Russian Text Copyright ? 2008 by R. R. Fazlyev, G. F. Vafina, and F. Z. Galin __________ Translated from Zhurnal Strukturnoi Khimii, Vol. 49, No. 6, pp. 1179–1181, November–December, 2008.     

Stark quantum beat spectroscopy: The vibrational dependence of the dipole moment in the A1Σ+ state of BaO

The method of quantum beat spectroscopy following pulsed dye laser excitation is applied to measure electric field splittings in excited states of the ¹³⁸Ba¹⁶O molecule. Stark quantum beats were observed in the fluorescent decay of the A¹Σ⁺ (ν′ = 0, 1, 2, 3, J′ = 1) states. From the observed beat frequencies values of electric dipole moments in different vibrational states were derived. The results are: μ(ν′ = 0) = 2.98(7) D, μ(ν′ = 1) = 2.66(7) D, μ(ν′ = 2)3.15(8) D and μ(ν′ = 3) = 3.18(8) D.     

Laser-fluorescence measurement of the 7LiD (X 1∑+) potential up to high vibrational quantum numbers

Sixteen new vibrational levels of ⁷LiD (X ¹∑⁺) were found by analysis of laser-excited fluorescence spectra. They extend up to ν″ = 20, corresponding to 82% of the dissociation energy of LiD. New rotational and vibrational constants were derived from the data and were used for an RKR calculation of the ⁷LiD (X ¹∑⁺) potential. Extra-polating this potential up to the dissociation limit gives agreement with the known dissociation energy to within 90 cm^?1.     

First observation of the M 2Σ+ → E2Σ+ (0—0) transition in NO

The emission spectrum of NO excited by electric discharge has been recorded with a high-resolution Fourier transform interferometer. Strong perturbations are observed in the spectrum of the transition M²Σ⁺→ E²Σ⁺ (0—0), due to mixing of the Rydberg state M²Σ⁺(v = 0) with valence states B²Π(v = 22, 23) and L²Π(v = 3). Accurate energies for the M²Σ⁺ rotational levels are given.     

Molecular structure of methyl 20-isopropyl-15(E)-hydroxyimino-5,9-dimethyl-18-oxahexacyclo [12.4.0.22,13.118,20.05,10.04,13]heneicosane-9-carboxylate

Methyl 20-isopropyl-15(E)-hydroxyimino-5,9-dimethyl-18-oxahexacyclo[12.4.0.2^2,13.1^18,20.0^5,10.0^4,13]-heneicosane-9-carboxylate is synthesized and its molecular structure is determined. Compound IIa of C₂₇H₄₁NO₄ crystallizes in the acentric P2₁ space group with the following unit cell parameters: a = 7.6511(7) ?,b = 12.0698(11) ?, c = 12.9182(12) ?, β = 95.257(2)°.     

Molecular structure of methyl-10,14,19,19-tetramethyl-4-oxo-20-oxahexacyclo [15.3.1.16.18.06.15.09.14017.21]docosane-10-carboxylate

The synthesis of methyl-10,14,19,19-tetramethyl-4-oxo-20-oxahexacyclo[15.3.1.1^6.18.0^6.15.0^9.140^17.21] docosane-10-carboxylate III is performed and its molecular structure is determined. Compound III C₂₇H₄₀O₄ crystallizes in the monoclinic system with the cell parameters as follows: a = 12.8081(11) ?, b = 7.0384(6) ?, c = 12.8904(12) ?, β = 105.828(2)^o, P2₁ space group, Z = 2, d = 1.273 mg/m³.     

Perturbations in the B3Π(0+) state of CIF: A new low-lying electronic state

Perturbations in the relational structure of the high-resolution laser excitation spectrum of the B³Π(O⁺-X¹Σ⁺ system of CIF have been observed. Details of these perturbations are given and are used to infer details about the perturbing state.     

Sensitization of the CN(B2Σ+ → X2Σ+) emission by Hg(63P0) metastables

The vibrational analysis of the CN(B²Σ⁺ → X²Σ⁺) emission sensitized by Hg(6³P₀) metastables has shown that the energy transfer process, Hg(6³P₀) + CN(X²Σ⁺) → Hg(6¹S₀) + CN(B²Σ⁺), populates the CN(B²Σ⁺) state in a non-Franck-Condon fashion. The relative vibrational populations for the ν = 0 to 4 states are 1.00, 0.56 ± 0.06, 0.26 ± 0.03, 0.11 ± 0.03 and 0.04 ± 0.01, respectively. Long-range attractive interaction between the Hg(6³P₀) atom and the CN(X²Σ⁺) radical is evidenced by the observed high rotational excitation of the CN(B²Σ⁺) radical following the energy transfer process.     

Vibrational deactivation of CO2(0001) by ethane

The deactivation of CO₂(00⁰1) by ethane in the temperature range 300–600 K has been studied using a laser induced fluorescence technique. The energy transfer cross section decreased from 0.23 Ų at 300 K to 0.16 Ų at 600 K. The magnitude of the cross section is consistent with the expectation that near resonant V-V energy transfer processes are responsible for the energy transfer between CO₂(00⁰1) and ethane during collisions even though the observed temperature dependence of the energy transfer cross section does not follow that predicted by the existing theories.     

Sensitization of the OH(A 2Σ+ → X 2Πi) emission by Hg(6 3P0) metastables

The electronic energy transfer process Hg(6 ³P₀) + OH(X²Π_i, υ = 0,K) → Hg(6 ¹S₀) + OH(A ²Σ⁺, υ,K) has been studied by the sensitized fluorescence method. A rather broad spectrum of rotational population, N_υ′K′, was obtained under conditions of minimum relaxation, which illustrates the non-resonant and non-optical nature of this energy transfer process. The fractions of the exoergicity, above electronic excitation of OH(A ²Σ⁺, υ = 0, K = 0), going into vibrational, rotational and translational excitation are 0.11, 0.31, and 0.58, respectively. A statistical mode of energy partitioning, such as would result from long-lived complex formation, seems to account well for these observations.     

Collisional vibrational relaxation in the A 2Π state of CN

Collisional vibrational relaxation of several vibrational levels of the A²Π state of CN has been investigated. A given excited level is prepared by cw dye laser excitation in the A²Π-X²Σ⁺ band system in a discharge-flow apparatus. The resulting fluorescence from the initially prepared and collisionally populated vibrational levels is observed as a function of rare gas pressure (Ar or He, 1–7 Torr). CollisionaI transfer rates for Δυ = ?1 transitions are extracted with the aid of a steady-state kinetic model. Emission from lower vibrational levels was also observed but could be explained by cascade processes, rather than direct Δυ > 1 collisional transitions.     

Molecular and crystal structure of 23,24,25,26,27,29,30-heptamethyl-19,28-oxahexacyclo[15.13.18.017,18.013,14.08,9.05,10]tetracos-3-yl acetate

The molecular structure of 23,24,25,26,27,29,30-heptamethyl-19,28-oxahexacyclo[15.13.18.0^17,18.0^13,14.0^8,9.0^5,10]tetracos-3-yl acetate III. Compound III C₃₂H₅₂O₃ crystallizes in the monoclinic crystal system with the unit cell parameters a = 13.265(15) ?, b = 6.481(7) ?, c = 32.274(4) ?, β = 99.333(2)°, space group C2, Z = 4, d = 1.176 g/cm³. Original Russian Text Copyright ? 2009 by N. I. Medvedeva, O. B. Flechter, and A. A. Korlyukov __________ Translated from Zhurnal Strukturnoi Khimii, Vol. 50, No. 2, pp. 399–401, March–April, 2009.     

b 1Σ+ and a 1Δ emissions from group VI—VI diatomic molecules: b0+ → X10+, X21 emissions of TeSe

Near-infrared emissions of the b0⁺ → X₁0⁺, X₂1 band systems of TeSe have been observed in a discharge flow system. Analysis of the spectra yielded T_e values of the X₂1 and b0⁺ states of 1235 ± 5 cm^?1 and 8794 ± 5 cm^?1, respectively, and a vibrational spacing in the b0⁺ state of ω_e(b) = 294 ± 3 cm^?1.     

Multiphoton ionisation detection of PH (PD) radicals in their b 1Σ+ electronic state

PH (PD) radicals in their b ¹Σ⁺ electronic state have been produced by three-photon excitation and dissociation of PH₃ (PD₃) and dete     

A photoelectron spectroscopic study of proximity effects in 8,11-disubstituted pentacyclo(5.4.0.02.6 .03,10 .05,9) Undecanes

Photoelectron spectra of six 8,11-disubstituted pentacycloundecanes (1, 3 - 7) are reported; the results suggest that the through-space interaction betweeen unsaturation centers in 1 and 3 dominates over the through-bond interaction mechanism.     

Picosecond fluorescence decays from vibrational levels in the S1(n,π*) state of pyridine vapor

Fluorescence lifetimes of pyridine vapor were measured by exciting at various vibrational bands in the lowest-energy region of the S₁(n,π^*) ← S₀ transition. The lifetime varies between 35 and 60 ps, depending on the vibronic level excited. The non-radiative decay from S₁ is characterized by particularly fast S₁ → S₀ internal conversion.