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1.
Gas-phase spectra of four isotopic species of GaBr have been detected in the millimeter wavelength region. The molecules were produced by a flame reaction of gallium and bromine at 1000° C. From the rotational spectra molecular constants have been determined for 69Ga79Br,69Ga81Br,71Ga79Br,71Ga81Br. The equilibrium internuclear distance is re = 2.3524907(82).  相似文献   

2.
At wavelengths near 1 mm the rotational transitionsJ=16←15 and 17←16 of the diatomic IF have been observed. The strong hyperfine transitions ΔF=+1 were measured in vibrational statesv=0, 1 and 2. The much weaker ΔF=0 components could be detected in the rotational transitionJ=17←16 of the molecule in its ground vibrational state. The analysis including previous measurements at larger wavelengths resulted in improved hyperfine parameters, an extended set of Dunham energy coefficients and potential constants.  相似文献   

3.
At wavelengths near 1 mm six rotational transitions of GaCl have been observed. The analysis including previous measurements on the rotational transitionJ = 1 ← 0 resulted in extended sets of the Dunham parametersY 01,Y 11,Y 21,Y 31,Y 02,Y 12 andY 03 of the four isotopic species69Ga35Cl,71Ga35Cl,69Ga37Cl and71Ga37Cl. With these microwave data the constantsY 10 ≈ εe and —Y 20 ≈ ω e x e were determined. The parameters of the Dunham potentiala 0,a 1,a 2,a 3 andr e are given. The GaCl was produced by reaction of gaseous CCl4 with Ga evaporated at 1,500°C.  相似文献   

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5.
The microwave spectrum of a second conformer of acrolein is reported for the first time. Ground-state rotational constants and quartic centrifugal distortion constants were determined from 42 transitions in the range 8–60 CHz. The small inertial defect establishes its planarity. The dipole moment of s-cis acrolein is μa = 2.010(5) D, μb = 1.573(3) D and μtotal = 2.552(3) D.  相似文献   

6.
The ground-state rotational spectra of 24 isotopomers of ethynylstannane have been observed by pulsed-jet, Fourier-transform microwave spectroscopy. The spectroscopic constants, B(0,)D(J) and D(JK) are reported for symmetric-top isotopomers H(3)(n)Sn(12)C(12)CH, where n = 116, 117, 118, 119, 120, 122 and 124, D(3)(n)Sn(12)C(12)CH, where n = 116, 118, 120, 122 and 124, H(3)(n)Sn(13)C(12) CH and H(3)(n)Sn(12)C(13)CH , where n = 116,118 and 120, and H(3)(n)Sn(12)C(12)CD, where n = 116, 118 and 120. In addition, the values of A(0), B(0), C(0), Delta(J) and Delta(JK) were obtained for the three asymmetric-top isotopomers DH(2)(n)Sn(12)C(12)CH, where n = 116, 118 and 120. Hyperfine structure was resolved and assigned in the transitions of the isotopomers H(3)(n)SnCCD, where n = 116, 118 and 120, and in the isotopomers H(3)(117)SnCCH and H(3)(119)SnCCH. In the former group, the hyperfine structure arises from D nuclear quadrupole coupling while in the latter group its origin lies in the spin-rotation coupling of the I = 1/2 Sn nuclear spin to the rotational motion. For these isotopomers, D nuclear quadrupole and spin-rotation coupling constants are determined where appropriate. The rotational constants obtained for the 24 isotopomers of H(3)SnCCH were used to obtain the following types of molecular geometry for ethynylstannane: r(0), r(s), and r(m).  相似文献   

7.
8.
The possibility of using the virial theorem to calculate the coefficients of the potential function for diatomic hydrides on the basis of the Fock-Roothaan wave function in the closed electron shell approximation has been demonstrated in relation to the LiH, BH, CH, NH, and OH molecules.  相似文献   

9.
We apply Wigner's effective-harmonic-oscillator (EHO) function with the Morse potential to the calculation of vibrational constants of diatomic molecules. A one-particle system is described by the operator representation of Wigner's function. We find the EHO parameters both for a single molecule and for an equilibrium ensemble of molecules. We obtain numerical values of the constants for the iodine molecule.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 24, No. 4, pp. 485–487, July–August, 1988.  相似文献   

10.
11.
Structure, spectroscopic constants and molecular properties of selected diatomic anions in their ground states have been studied in detail using HF/DF B3LYP method. The consistency of the calculated values of spectroscopic constants and molecular properties has been tested using four basis sets with improved quality. The spectroscopic constants and molecular properties of these diatomic ions agree well with the experimental and theoretical values wherever available. Most of the spectroscopic constants and molecular properties of these ions, in particular the spectroscopic constants of SiO, CS and the molecular properties of SiN, CP, SiO are first reported.  相似文献   

12.
The results of earlier studies of diatomic forces and force constants are used to formulate force constraints. It is proposed that such constrained variations should improve force constant calculations.
Zusammenfassung Mittels früherer Ergebnisse für Bindungskräfte bei zweiatomigen Molekülen werden Neben-bedingungen für die Wellenfunktion formuliert. Es ist anzunehmen, da\ dies zu einer Verbesserung der Berechnung für die entsprechenden Kraftkonstanten führt.

Résumé Les résultats d'études antérieures des forces et des constantes de force diatomiques sont utilisés pour formuler des contraintes de force. De telles variations contraintes devraient améliorer les calculs de constante de force.
  相似文献   

13.
A new procedure is described to determine the geometrical structure of a molecule. It starts from measured ground state rotational constants of isotopically substituted species. Internal structural parameters such as bond lengths, bond angles and dihedral angles are directly fitted with a suitable least-squares algorithm. The new method for structure determination is compared to the usual Costain—Kraitchman substitution method. It contains less stringent conditions than the latter, permits a broad range of applications and provides a reliable molecular structure.  相似文献   

14.
The ground-state microwave spectrum of methyl iodide has been measured between 59 and 240 GHz with a molecular beam spectrometer and by use of the Lamb dip method. The following molecular parameters have been accurately determined: B = 7501275.70(2) kHz; DJ = 6.3070(2) kHz; DJK = 98.762(3) kHz; HJ = ?0.0051(6) Hz; HJK = 0.04(2) Hz; HKJ 4.51(3) Hz; eq. Q = ?1934.136 (5) MHz; C= ?17.40(6) kHz; C| = ?19.4(5) kHz; xJ = ?1.41(4) kHz; xK = ?38(1) kHz and xd = 26.2(6) kHz. The last three constants characterize the interaction of centrifugal distortion with quadrupole coupling. The data are used to determine the elements of the iodine nuclear magnetic shielding tensor. Comparisons of the shielding are made for molecules which contain one iodine atom.  相似文献   

15.
16.
57Fe Mössbauer spectra have been obtained for Fe(p-CH3C6H4SO3)2 between 2.3 and 300 K in zero field, and at 2.3 and 4.2 K in longitudinal applied magnetic fields ranging from 1.1 to 5.6 T. The complex is a fast-relaxing paramagnet under all conditions studied and there is no evidence of antiferromagnetic exchange coupling. The FeO6 chromophore is distorted by a trigonal elongation and the orbital ground state is the [(23)12|±2〉 ? (13)12|?1〉] doublet. The temperature dependence of the quadrupole splitting has been analysed via a crystal-field model to provide estimates of the axial field splitting parameter Ds = -93 cm-1, spin-orbit coupling constant λ = -70 cm-1, and fine structure constant Dσ = -28 cm-1. The magnetic properties of the complex are described by treating the ground state as a non-Kramers doublet with fictitious spin ? = 12. Five separate Mössbauer-Zeeman spectra can be fitted in this spin-hamiltonian approximation with identical values of the g- and A-tensor components, viz. g = 1.0, gu = 9.0; A ≈ 2.0 mm s-1. Au = -1.79 mm s-1. The trigonal z axis, the z axis of the electric field gradient tensor, and the easy axis of magnetisation are collinear, and the saturation value of the internal hyperfine field along this axis is +13.0 T.  相似文献   

17.
Based on a new criterion that was proposed to search for the universality of spectroscopic constants for bound ground-state diatomics [R. H. Xie and P. S. Hsu, Phys. Rev. Lett. 96, 243201 (2006)], we have found universal scaling relations between spectroscopic constants of diatomic systems with s-, p-, and d-type valence-shell constituents. Our study suggests a useful empirical approach for the prediction of molecular spectroscopic constants.  相似文献   

18.
19.
The rotational spectrum of the molecular negative ion CN(-) has been detected in the laboratory at high resolution. The four lowest transitions were observed in a low pressure glow discharge through C(2)N(2) and N(2). Conclusive evidence for the identification was provided by well-resolved nitrogen quadrupole hyperfine structure in the lowest rotational transition, and a measurable Doppler shift owing to ion drift in the positive column of the discharge. Three spectroscopic constants (B, D, and eQq) reproduce the observed spectrum to within one part in 10(7) or better, allowing the entire rotational spectrum to be calculated well into the far IR to within 1 km s(-1) in equivalent radial velocity. CN(-) is an excellent candidate for astronomical detection, because the CN radical is observed in many galactic molecular sources, the electron binding energy of CN(-) is large, and calculations indicate CN(-) should be detectable in IRC+10216-the carbon star where C(6)H(-) has recently been observed. The fairly high concentration of CN(-) in the discharge implies that other molecular anions containing the nitrile group may be within reach.  相似文献   

20.
A novel method has been developed to evaluate accurate rotational constants from the microwave spectrum of the unstable molecule bromine isocyanate, using perturbations in nuclear quadrupole hyperfine structure. It has been applied to this prolate near-symmetric rotor to determine Av and xab accurately, entirely from a-type R branches. The method has been made possible by the development of a special computer program for global léast-squares fitting to rotational and centrifugal distortion constants, along with all components of the Br nuclear quadrupole coupling tensor.  相似文献   

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