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1.
The transitions J = 1 ← 0, K = 0; J = 2 ← 1, K = 0; and J = 2 ← 1, K = 1 of CH3I and CD3I were measured using a Stark-modulated microwave spectrometer. Iodine quadrupole coupling strengths were analyzed to determine variations with deuterium substitution on the methyl group and variations with centrifugal distortion. Quadrupole coupling strengths were described by the expression eQq0 + aJ(J + 1) + bK2 + cK4J(J + 1). Explicit expressions are given for a, b, and c for a symmetric top in terms of molecular parameters. For CH3I eQq0 = ?1934.11 ± 0.02 MHz and for CD3I eQq0 = ?1928.95 ± 0.04 MHz. Rotational constants obtained are B(CH3I) = 7501.274 ± 0.002 MHz and B(CD3I) = 6040.298 ± 0.007 MHz. The observed fractional change in halogen quadrupole coupling of 0.0027 is related to previous results for methyl chloride and methyl bromide.  相似文献   

2.
The region 2242–2273 cm?1 of the ν4 band in CD3Br was remeasured at a resolution limit of 0.025 cm?1. Line assignments were extended up to J = 50 in some subbands. Transitions in the KΔK = ?8 subband were assigned, and the perturbation apparent in this region was attributed to the x-y Coriolis interaction with ν3 + ν5±1 + ν6±1. The x-y Coriolis coupling parameter Wxu and the ν3 + ν5±1 + ν6±1 band center (in cm?1) are 0.01960 and 2339.17 for CD379Br, while the corresponding values for CD381Br are 0.01956 and 2337.95.  相似文献   

3.
The J = 1-0 transitions in 35ClCCD were measured using a beam maser spectrometer giving a molecular resonance linewidth of 3 kHz (FWHM). Analysis of the data yielded quadrupole coupling strengths eqQ(D) = 208.5 ± 1.5, eqQ(35Cl)= 79 739.5 ± 1 kHz and the 35Cl spinrotation interaction strength C(Cl) 1.3 ± 0.1 kHz. The rotational constant obtained is B = 5 186 973.9 ± 1.0 kHz. The accuracy of measured molecular parameters is improved by a factor of 20 or better.  相似文献   

4.
Microwave spectra have been studied in the ground and v5 = 1 (CC stretching mode) states of methylacetylene. From these data, dipole moments and rotational and centrifugal distortion constants have been determined, as follows: μD(0) = 0.7839 ± 0.0010 D, μD(5) = 0.7954 ± 0.0010 D, B5 = 8508.119 ± 0.003 MHz, DJ(5) = 1.8 ± 0.2 kHz, and DJK(5) = 169 ± 1 kHz. Laser Stark spectra have been obtained for the ν5 band of this molecule and from these spectra the following vibration-rotation parameters have been determined: ν50 = 93.27540 ± 0.00007 cm?1, A5 - A0 = ?227.0 ± 2.3 MHz and DK(5) - DK(0) = ?0.05 ± 0.50 MHz. The higher-J and -K states of the v5 = 1 state appear to be purturbed.  相似文献   

5.
The highly sensitive method of infrared-radiofrequency double resonance inside a CO2N2O laser cavity has been applied to the observation of “pure” nuclear quadrupole resonance and direct A1-A2 transitions of CH3Br. More than 150 quadrupole resonances have been observed for 12CH379Br, 12CH381Br, 13CH379Br, and 13CH381Br using direct double resonance as well as collision-induced satellites. Accurate hyperfine constants, i.e., the quadrupole coupling constant eqQ and its rotational dependence χJ and χK, Hougen's coefficient χd, and the spin-rotation constants CN and CK have been determined for the ground state. The eqQ in the excited states ν3, ν6, ν3 + ν6, and 2ν6 have also been determined. About 60 direct l-doubling transitions have been observed, which has enabled us to determine the l-doubling constant qv(1,1), its rotational dependence δqvJ(1,1) and the asymmetry parameter for the quadrupole coupling constant eqQη for the ν6 and ν3 + ν6 states. A set of direct A1-A2 transitions in the 2ν6 state with K = 1 and l6 = ?2 and that in the ν6 state with K = 2 and l6 = ?1 have been observed. The rovibrational and isotope assignments of the observed A1-A2 are helped by the existence of quadrupole hyperfine structure and many collision-induced satellites. The rovibrational assignments of CH3Br transitions which are coincident with laser lines are summarized.  相似文献   

6.
Electric quadrupole coupling constant eqQ/h of the extremely proton-rich 23Al (I π ?=?5/2?+?, T 1/2?=?0.47 s) nucleus implanted into an Al2O3 single crystal has been measured for the first time, using the β-ray detecting nuclear quadrupole resonance method (β-NQR) in a high magnetic field. As a preliminary result, the quadrupole coupling constant was determined as |eqQ/h(23Al) |?=?2.66±0.77 MHz. Using the quadrupole coupling constant of 27Al in Al2O3 as a reference, the Q moment of the ground state of 23Al was extracted as |Q(23Al)|?~?160 mb, which is well explained by the shell model calculation in the sd-shell model space with the USD interaction.  相似文献   

7.
Measurements of the rotational spectrum of the C4v molecule IOF5 are reported for the excited vibrational state v11(E) = 1 for the transitions J13 ← 12, 14 ← 13, 16 ← 15, and 17 ← 16 (55–72 GHz) including the observation of the kl = −1 (q), l-doubling effect. Detailed assignments of the E-state spectrum are presented based on the overlapping quadrupole structure. These data are analyzed together with earlier results for the excited vibrational state v6(B1) = 1 to give information concerning the ν6(B1)-ν11(E) Coriolis interaction and the (Δl, Δk) = (2, 2) (q+) and (2, −2) (q)l-resonance interactions. It is found that q11 = −2.57(10) MHz, |q11+| = 0.094(20) MHz, Δ = ν6ν11 = 45.2(7) cm, ζ11,11z = +0.18(1) and |ζ6,11y| = 0.73(4).  相似文献   

8.
The principles and methods of determining A0 from the Raman spectra of degenerate fundamentals of C3v molecules are outlined, and applied to the ν4 band of CD3Br to yield a value of A0 = 2.6004 ± 0.0010 cm?1.  相似文献   

9.
The microwave spectra of three isotopic species of methoxyamine (CH3ONH2) have been studied. For the normal species the ground-state rotational constants are A = 42488 ± 150 MHz, B = 10049.59 ± 0.03 MHz, and C = 8962.85 ± 0.03 MHz. From these data and those from the -NHD and -ND2 species, the amino protons have been shown to occupy a symmetrical trans position relative to the methyl group. The barrier to internal rotation of the methyl group has been found to be 873 ± 15 cm?1 by analysis of ground-state splittings. Analysis of hyperfine splittings has yielded the 14N quadrupole coupling constants, which have the following values for the normal isotopic species: χaa = 3.63 ± 0.03 MHz, χbb = ?3.69 ± 0.07 MHz, and χcc = 0.06 ± 0.07 MHz.  相似文献   

10.
The J = 4 ← 3 and J = 3 ← 2 rotational transitions of 1-phosphapropyne, CH3CP, between 26.5 and 40 GHz have been studied by microwave spectroscopy. The spectrum shows the characteristic vibration-rotation satellite patterns associated with a C3v symmetric rotor. Apart from the most abundant isotope variant, the species 12CD312C31P, 12CD2H12C31P, 12CH2D12C31P, 13CH312C31P, 12CH313C31P, 13CD312C31P, and 12CD313C31P have also been studied. For 12CH312C31P the rotational constants B0 = 4991.339 ± 0.003 MHz, DJ = 0.823 ± 0.092 kHz, DJK = 66.59 ± 0.18 kHz have been determined. From these data the following structural parameters have been derived: rs(CH) = 1.107 ± 0.001 A?, ∠s(HCC) = 110.30 ± 0.09°, rs(CC) = 1.465 ± 0.003 A?, r0(CP) = 1.544 ± 0.004 A?. The dipole moment has been determined as 1.499 ± 0.001 D by analysis of the Stark effect of the J = 3 ← 2, |K| = 1 line. The vibrational satellites (vs = 1, 2, and 3) have been studied and various vibration-rotation parameters derived.  相似文献   

11.
The bending vibration-rotation band ν4 of DCCF was studied. The measurements were carried out with a Fourier spectrometer at a resolution of about 0.03 cm?1. The constants B0=0.29141(1)cm?1, α4=?5.02(2)×10?4cm?1, q4=4.52(3)×10?4cm?1, and D0=9.2(4)×10?8cm?1 were derived. The rotational analysis of the “hot” bands 2ν4(Δ) ← ν4(II) and 2ν4+) ← ν4(II) was performed. In addition, the “hot” bands ν4 + ν5 ← ν5 were assigned. A set of vibrational constants involved was derived.  相似文献   

12.
The bands ν2 and ν5 of CD3Br have been measured at a resolution of 0.010 cm?1. They were analyzed simultaneously by taking into account the xy-Coriolis interaction. More than 1600 transitions were assigned for each isotopic species CD379Br and CD381Br. The Coriolis coupling term proved to be ζ2,5y = 0.559. The band centers are (in cm?1) ν2: 991.401 (CD379Br), 991.390 (CD381Br); ν5: 1055.474 (CD379Br), 1055.471 (CD381Br).  相似文献   

13.
The rotational spectra of SO279BrF and SO281BrF have been obtained between 18 and 40 GHz. Both molecules are near-prolate symmetric rotors with a and b-type dipole components. A least-squares fit of the observed moments of inertia obtained by correcting for the bromine quadrupole interaction yields r(SBr) = 2.155 ± 0.006 A? and ? FSBr=100.6°±1.5° structural parameters when r(SO) = 1.407 A?, r(SF) = 1.56 A?, and ? OSO=123.7° are assumed.  相似文献   

14.
Dipole moment functions, both perpendicular and parallel to the molecular axis, are calculated from the SCF and MRD-CI results of a previous study for the normal ν2 bending vibrations of HCN and DCN. Vibrationally averaged dipole moments and the infrared transition matrix elements are then obtained from the dipole moment functions and vibrational wave functions. MRD-CI results, with known experimental values in parentheses, for HCN are 〈0|μ|0〉 = ?2.954(?2.985) D, 〈1|μ|1〉 = ?2.915(±2.942) D, 〈0|μ|1〉 = 0.148(0.147) D, 〈0|μ|2〉 = ?0.027 D, 〈1|μ|2〉 = 0.210 D. Calculated absolute intensities at 1 atm and 0°C for the (0200) ← (000), (0200) ← (010), and (0220) ← (010) bands of HCN are 25 (40 ± 10 as estimated from spectra), 8.5, and 17.0 atm?1 cm?2, respectively. Results for DCN are also reported.  相似文献   

15.
The bending vibration bands ν4 and ν5 of HCCI were studied. From the observed rotational structure the rotational constant B0 and the centrifugal distortion constant D0 were obtained. The results were B0 = 0.105968(7) cm?1 and D0 = 1.96(7) × 10?8 cm?1 from ν4 and B0 = 0.105948(8) cm?1 and D0 = 1.96(11) × 10?8 cm?1 from ν5. The structure of the hot bands 2ν5(Δ) ← ν5(Π) and 3ν5(φ) ← 2ν5(Δ) was also resolved and hence the values α5 = ?3.033(8) × 10?4 cm?1 and q5 = 9.3(3) × 10?5 cm?1 could be derived. The other most intense hot bands following ν5 could be explained in terms of the Fermi diads ν350 and ν3 + ν5±15±1. Of the numerous hot bands accompanying ν4, only those between different excited states of ν4 could be assigned. Then estimates for α4 and q4 were also obtained. In addition, several vibrational constants were derived.  相似文献   

16.
The microwave spectrum of 4-pyridine carbaldehyde has been investigated in the region 8 to 40 GHz. Rotational transitions have been observed and assigned for the ground state and two excited states of the torsion mode. Analysis yields precise rotational constants (A = 5519.04 ± 0.08, B = 1559.17 ± 0.03, C = 1216.11 ± 0.02 MHz) which prove the molecule to be planar. Centrifugal distortion constants have also been obtained. Analysis of the observed 14N quadrupole fine structure yields the following quadrupole coupling constants (in MHz): χaa = ?4.67 ± 0.09; χbb = 1.19 ± 0.26; χcc = 3.48 ± 0.26. The electric field gradient about the nitrogen nucleus is thus similar to that of pyridine.  相似文献   

17.
The ν2 fundamental band of CD3I was investigated by means of the laser Stark spectroscopy using a 10.6 μm CO2 laser and an N2O laser as infrared radiation sources. The assignment was established for about 150 Stakr resonances. Laser-microwave double resonance was used to confirm the assignment. A least-squares analysis of the Stark spectrum gave the molecular constants: μ″ = 1.6504 ± 0.0004 D; μ′ = 1.6479 ± 0.0005 D; ν0 = 28 461 093.8 ± 3.6 MHz; A′ - A″ = 234.0 ± 1.1 MHz; DK′ - DK″ = 0.121 ± 0.085 MHz. The uncertainties are 2.5 times the standard deviations. The single and the double primes refer to the ν2 and the ground vibrational states, respectively.  相似文献   

18.
Improved production yields of short-lived halogens were obtained from a ThO2 target, irradiated with 600 MeV protons, in combination with a negative surface ionization source. Mass-separated samples were studied by decay spectroscopy. Production yields of radioactive isotopes of chlorine, bromine, iodine and astatine are presented. Half-lives and relative neutron emission probabilities were measured for the heavy bromine isotopes89?92Br. Normalizing to earlier publishedP n values for89Br, the results are:89Br (4.30±0.14s,P n =13.6±0.8%),90Br (1.92±0.06s,P n =24.8±1.5%),91Br (0.53 ±0.03 s,P n =30.1 ±2.1%), and92Br (0.31 ±0.02 s,P n =34.6±2.5%). Energy spectra ofβ-delayed neutrons were measured.  相似文献   

19.
The J = 1 ← 0 and J = 2 ← 1 transitions and the l-doubling transitions of J = 2 – 6 of 12CH3F in the ν2 and ν5 states were analyzed by taking into account the Coriolis interaction between the two modes. The molecular constants which are derived are: ν5 - ν2, 252 412 ± 112; B51, 25 611.60 ± 0.40; Aζ5, ?38 772 ± 116; B21, 25 432.52 ± 0.33; D, 21 838.4 ± 8.2; q51, 39.58 ± 0.30 MHz; in addition to a few other minor constants. The present result is completely consistent with the recent Raman data of Escribano, Mills, and Brodersen, J. Mol. Spectrosc.61, 249 (1976). Molecular constants in the ν3 and ν6 states have also been obtained: B3, 25 197.570 ± 0.020; B6, 25 418.917 ± 0.047; Aζ6ηJ, ?0.562 ± 0.030; |q6|, 8.70 ± 0.13 MHz. Errors are 2.5 times the standard deviations.  相似文献   

20.
Mössbauer studies of the 84.3 keV gamma ray of Yb170 emitted from Yb in TmxHo1?xFe2 at various temperatures were performed. These yield the crystalline field parameters (A4r4〉 = 36 ± 5 K, A6r6〉 = -3 ± 2K, the exchange field (μBHexch = 116 ± 4 K) and the Yb3+ free ion hyperfine constants (H4f = 4100 ± 150 kOe, eqQ = 2400 ± 250 MHz and H (conduction electrons) = 350±100 kOe). Spin relaxation phenomena observed in TmFe2 at low temperatures give a value of ~ 0.03 for |?(EF)Jsf|. Spectra observed in Tm0.2Ho0.8Fe2 in the spin reorientation transition region indicate that the transition is of second order.  相似文献   

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