The Rotational Spectrum of Monothioformic Acid. I. cis-and trans-HC(:O)SH1,2

1976 ◽  
Vol 31 (5) ◽  
pp. 422-437
Author(s):  
William H. Hocking ◽  
Gisbert Winnewisser

Abstract The rotational spectra of the two abundant isomers of monothioformic acid, cis- and trans- HC(:O)SH, have been assigned in the frequency region 8 -250 GHz. Over 90 a-type transitions and over 60 b-type transitions have been measured for each rotamer. The a-type transitions belong to the qRK , qQ1, qQ2, qQ3 and qQ4 branches and the b-type absorption lines encompass the Ka = 1 - 0, 2 - 1, 3 - 2, 4 - 3 and 5 - 4 rotational sub-bands. The rotational constants and all quartic and sextic centrifugal distortion constants have been determined for each rotamer using Watson's reduced Hamiltonian. In addition to the measured line positions the frequencies of some selected low-J transitions, not observed in this work but of potential astrophysical interest, have been listed as an aid in the interstellar search for monothioformic acid.

1975 ◽  
Vol 30 (8) ◽  
pp. 1001-1014 ◽  
Author(s):  
Manfred Winnewisser ◽  
Gisbert Winnewisser ◽  
T. Honda ◽  
E. Hirota

Abstract The pure rotational spectrum of trans-acrolein in the ground vibrational state has been assigned in the frequency region from 8 GHz to 180 GHz. The measured absorption lines encompass a-type transitions from the qRK, qQ1, qQ2 branches and 6-type transitions from the rP0, rP1, rP2, rR0 brandies for values of J up to 23. The rotational constants have been refined and all quartic and sextic centrifugal distortion constants have been determined using Watson's reduced Hamiltonian. This information has been used to predict line positions of astrophysical interest to warrant the interstellar line search for trans-acrolein.


2003 ◽  
Vol 58 (5-6) ◽  
pp. 275-279 ◽  
Author(s):  
A. Guarnieri ◽  
A. Huckaufa

The pure rotational spectra of [18O]ketene, H2C=C18O, [1-13C]ketene, H2C=13CO, and [2-13C]ketene, H213C=CO, have been revisited in the frequency region 200 - 350 GHz in the ground vibrational state.From more than 100 R-branch transitions for each isotopomer a set of rotational and centrifugal distortion constants could be derived using the Watson S-reduction formalism. The values obtained for the rotational constants B and C agree very well with results of former investigations. The agreement is worse with respect to the A constants, but our newly determined A values agree well with the corresponding values of the main species and the 17O isotopomer.


1976 ◽  
Vol 31 (5) ◽  
pp. 438-453
Author(s):  
William H. Hocking ◽  
Gisbert Winnewisser

Abstract The rotational spectra of three isotopically substituted species of monothioformic acid, DCOSH, HCOSD, HCO34SH, have been investigated. Transitions arising from two different isomeric forms have been observed in each instance. Rotational constants and quartic centrifugal distortion constants have been determined for all species using Watson’s reduced Hamiltonian. It has been established that the two abundant isomers of monothioformic acid are the planar cis and trans thiol rotamers. The structure of cis-HC ( :O ) SH is found to be: r ( C - H ) =1.100 Å, r ( S - H ) =1.336 Å, r ( C - S ) =1.771 Å, r(C=0) =1.210 Å, ∢(OCS) =122.4°, ∢(HSC) =94.7° and ∢(HCS) = 114.6°; whereas for trans-HC ( :O ) SH: r(C - H ) =1.100 Å, r (S - H) =1.351 Å, r (C - S) = 1.763 Å, r(C=O) = 1.218 Å, ∢(OCS) =126.0°, ∢(HSC) = 92.7 ° and ∢(HCS) =111.8°.


1975 ◽  
Vol 30 (5) ◽  
pp. 672-689 ◽  
Author(s):  
Koichi Yamada ◽  
Manfred Winnewisser

Abstract The pure rotational spectrum of vinyl isocyanide in the ground vibrational state has been as-signed in the frequency region from 8 GHz to 180 GHz. The measured absorption lines encompass 157 a-type transitions from the qRK , qQ1, qQ2,qQ3, qQ4 and qQ5 branches and 48 b-type transitions from the rP0 , rP1, rP2, rP3 , rP4 , rP5, rQ0 , and rQ1 branches for values of J up to 54. The rotational constants have been refined and all quartic and sextic centrifugal distortion constants have been determined using Watson's reduced Hamiltonian. No quadrupole hyperfine splitting was observed.


1991 ◽  
Vol 46 (9) ◽  
pp. 770-776 ◽  
Author(s):  
Kirsten Vormann ◽  
Helmut Dreizler ◽  
Jens Doose ◽  
Antonio Guarnieri

AbstractThe boron and nitrogen hyperfine structure in the rotational spectra of two aminoborane isotopomers, 11 BH2NH2 and 10BH2NH2, has been investigated and the quadrupole coupling constants of boron 10B, 11B and nitrogen 14N have been determined. We get the following results for the nuclear quadrupole coupling constants: χaa(11B) = -1.684 (14) MHz, χbb(11B) = -2.212 (11) MHz, χcc(11B) = 3.896(11) MHz, χaa(10B) = -3.481 (11) MHz, χbb(10B) = -4.623 (14) MHz, χCC(10B) = 8.104 (14) MHz and xaa(14N) = 0.095 (9) MHz, χbb(14N) = 2.091 (8) MHz, χcf4 (14N)=-2.186 (8) MHz. These nitrogen quadrupole coupling constants are those of the 11BH2 NH2 isotopomer. Additionally we were able to determine two out of the three spin rotation coupling constants caa, cbb, and ccc of boron, caa(11 B = 55.2 (26) kHz, cbb(11B) = 6.62 (36) kHz, caa (10B) = 15.26 (69) kHz and cbb(10B) = 4.94 (70) kHz. The spin rotation coupling constants ccc had to be fixed to zero in both cases. Furthermore we measured the rotational spectra in the mm-wave region to determine all quartic and several sextic centrifugal distortion constants according to Watson's A and S reduction


1991 ◽  
Vol 46 (10) ◽  
pp. 909-913
Author(s):  
◽  
Helmut Dreizler

AbstractThe boron and nitrogen hyperfine structure in the rotational spectra of aminodifluoroborane has been investigated and the quadrupole coupling constants of 11B and nitrogen have been determined. We get the following results for the nuclear quadrupole coupling constants: Χaa(11B) = - 1.971 (6) MHz, Xbb(11B) = 0.500(11) MHz, Xcc(11B) - 2.471 (11) MHz, and Xaa(14N) = 0.890 (5) MHz, Xbb(14N) = 2.303 (7) MHz, Xcc(14N) = - 3.193 (8) MHz. Additionally we determined rotational and centrifugal distortion constants according to Watson's A reduction.


1994 ◽  
Vol 72 (11-12) ◽  
pp. 1206-1212 ◽  
Author(s):  
Mitsuaki Izuha ◽  
Satoshi Yamamoto ◽  
Shuji Saito

The rotational spectra of silacyclopropenylidene, c-C2H2Si, and its isotopic species (C2H229Si, C2D2Si, 13C2H2Si) were observed in the frequency region of 220–400 GHz by using a source-modulated microwave spectrometer combined with a free space absorption cell. c-C2H2Si was produced in the cell by discharging a mixture of SiH4, C2H2, and He. Least-squares analyses of the observed spectral lines yielded the rotational constants and the centrifugal distortion constants for the normal and its isotopic species. From the observed rotational constants, the rs structure was determined: rs (C=C) = 1.3458 Å, rs (C—Si) = 1.8200 Å rs (C—H) = 1.0795 Å, and [Formula: see text]. (1 Å = 10−10 m.)


1985 ◽  
Vol 63 (9) ◽  
pp. 1173-1183 ◽  
Author(s):  
Udai P. Verma ◽  
Klaus Möller ◽  
Jürgen Vogt ◽  
Manfred Winnewisser ◽  
Jørn Johs. Christiansen

The rotational spectrum of diazirine-d2, [Formula: see text], has been recorded in the ranges 8–40 and 100–400 GHz. The hyperfine structure of the measured rotational lines has been analyzed. The analysis required the treatment of two pairs of equivalent nuclei, which is discussed in detail. The deduced deuterium nuclear-quadrupole coupling constants are[Formula: see text]The quadrupole coupling constants of the nitrogen nuclei[Formula: see text]are taken from the parent species, and the spin-rotation coupling constants are[Formula: see text]The rotational and centrifugal distortion constants have been obtained for the ground vibrational state from the analysis of the unperturbed line positions. The complete rs structure of diazirine has been determined using the rotational constants of all available isotopomers of diazirine. The internuclear distances are rs(C—N) = 148.13(24) pm, rs(C—H) = 108.03(29) pm, and rs(N—N) = 122.80(25) pm, and the bond angles are [Formula: see text] and [Formula: see text], with the HCH plane perpendicular to the NCN plane.


The rotational spectra of six isotopic species of HCN∙ ∙ ∙HF in their vibrational ground states have been observed by pulsed-nozzle, Fourier-transform, microwave spectroscopy and have been analysed to yield the rotational constants B 0 , centrifugal distortion constants D J and various hyperfine coupling constants X i (D), X 3 ( 14 N) and D 4, 5 as follows (subscripts refer to the numbering scheme H (1) C (2) N (3) ∙ ∙ ∙H (4) F (5) ). isotopic species B 0 / MH Z D J /kH Z X i (D)/kH Z X 3 ( 14 N)/MH Z D 4, 5 (H, F)/kH Z HC 15 N∙ ∙ ∙HF 3573 5874(2) 6.97(2) ─ ─ –242(6) HC 15 N∙ ∙ ∙DF 3551.5110 6.83 269(4)( i = 4) ─ ─ HC 14 N∙ ∙ ∙HF 3591.1552 6.99 ─ –4.098(4) –218(6) HC 14 N∙ ∙ ∙DF 3569.6576 6.86 259(2)( i = 4) –4.096(1) ─ DC 15 N∙ ∙ ∙HF 3360.3549 5.85 186(5)( i = 1) ─ –244(4) DC 15 N∙ ∙ ∙DF 3338.0824 5.81 { 181(10) ( i = 1) ─ ─ 283(7) ( i = 4) The B 0 values lead to conclusions about the dimer geometry, the D J values allow the hydrogen bond stretching force constant k σ to be determined and the hyperfine coupling constants provide information about the internal dynamics of the subunits. An analysis of the D nuclear quadrupole coupling and H, F nuclear spin nuclear-spin coupling constants demonstrates that the H—F bond lengthens by 0.14 Å when the heterodimer HCN∙ ∙ ∙HF is formed. (1 Å = 10 –10 m = 10 –1 nm.)


1977 ◽  
Vol 32 (2) ◽  
pp. 183-184 ◽  
Author(s):  
Vijay Kumar Kaushik ◽  
Putcha Venkateswarlu

The microwave rotational spectrum of Nitric Acid has been analysed in the frequency region 8000-35000 MHz and up to J=12. The analysis gives refined rotational constants and all the quartic centrifugal distortion constants


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