scholarly journals Study of Millimeter-Wave Rotational Spectra ofTrioxane in Ground, v(A), v1(E) = 1 and v2(E) = 1 States

2009 ◽  
Vol 6 (s1) ◽  
pp. S259-S279 ◽  
Author(s):  
Masoud Motamedi ◽  
Najmehalsadat Khademi

The millimeter-wave rotational spectra of the ground and excited vibrational states v(A), v1(E) =1 and v2(E ) =1 of the oblate symmetric top molecule, (CH2O)3, have been analyzed again. The B0= 5273.25747MHz, DJ= 1.334547 kHz, DJk= -2.0206 kHz, HJ(-1.01 mHz), HJK(-3.80 mHz), and HKJ(4.1 mHz) have been determined for ground state. For non degenerate excited state, vA(1), the B = 5260.227723 MHz and DJand DJKwere determined 1.27171 kHz and -1.8789 kHz respectively. The 1=±1 series have been assigned in two different excited states v1(E) =1 and v2(E) =1.Most of the parameters were determined with higher accuracy compare with before. For the v2(E) =1 state the Cζ=-1940.54(11) MHz and qJ= 0.0753 (97) kHz were determined for the first time.

2008 ◽  
Vol 5 (4) ◽  
pp. 946-962
Author(s):  
Masoud Motamedi ◽  
Tahere Zohrevand

The millimeter-wave rotational spectra of the ground and excited vibrational states v7=1 and v8=1 of the symmetric top molecule, CCl3CN, have been analyzed again. The B0= 1666.80894(13) MHz, DJ= 0.135023 (23) kHz, DJK= 0.60596 (45) kHz, HJ= -0.0192 (10) mHz, HJK= 1.188 (34) mHz and HKJ= -1.60 (21) mHz have been determined for ground state. The 𝓁 = ±1 series have been assigned and the rotational parameters including B7=1667.96659(25) MHz, (q+t)7=1.58855(94) MHz for v7=1 and B8=1667.08204 (31) MHz, (q+t)8= 1.6141(36) MHz for v8= 1 states were determined accurately.


1971 ◽  
Vol 26 (1) ◽  
pp. 128-131 ◽  
Author(s):  
Manfred Winnewisser ◽  
Brenda P. Winnewisser

Abstract A newly designed millimeter-wave spectrometer has been employed for precise measurements of the millimeter-wave rotational spectrum of HCNO. Absorptions in several excited vibrational states as well as the ground state could be measured. The present paper presents the observed frequen­ cies and molecular constants obtained for the ground state and the first excited state of v4 and of v5, the vibrational bending modes


1979 ◽  
Vol 34 (3) ◽  
pp. 340-352 ◽  
Author(s):  
Harold Jones ◽  
H. D. Rudolph

Abstract The microwave spectrum of HCCF and DCCF has been investigated in all vibrational states with energy up to 1500 cm -1 . In the ground state and low-lying vibrational states mm-wave measurements up to 210 GHz were made. In some cases a detailed analysis of the vibrational state rotation spectrum including the effects of l-type resonance, and the determination of the anharmonicity constant gtt was possible. The rotational spectra of combination states of the type (vt = 2, vt′ = 1) were observed and partially analyzed, which is, to our knowledge, the first time this has been accomplished. The low-lying vibrational states of 13 C species of HCCF and DCCF were also observed. The 9.4 μm P(14) CO2-laser line was observed to produce a reduction in intensity in the ground state and an increase in intensity in the v3 = 1 excited state J = 0 → 1, 1 → 2, 2 3 transitions of DCCF.


1992 ◽  
Vol 47 (12) ◽  
pp. 1197-1203
Author(s):  
Wolfram Bodenmüller ◽  
Andreas Ruoff ◽  
Laurent Manceron

Abstract The infrared spectrum of the v12 fundamental and its accompanying hot band v12 + v14 - v14 of triazine has been measured by means of a Fourier transform spectrometer with a resolution of about 0.0023 cm-1 . A total of about 2779 rovibrational transitions has been assigned. The ground state constants have been considerably improved whilst the parameters for the excited states v12 = 1, v14 = 1 and v12 = v14 = 1 have been obtained for the first time. The standard deviations were 2.92 • 10-4 cm-1 for the ground state constants and 1.53 • 10-4 cm -1 for the excited state parameters of v12 showing the latter to be unperturbed. The upper state of the hot band v12 + v14 - v14 was found to be perturbed by an accidental resonance.


2009 ◽  
Vol 6 (3) ◽  
pp. 849-865 ◽  
Author(s):  
Masoud Motamedi ◽  
Tahere Zohrevand

The millimeter-wave rotational spectra of the ground and excited vibrational states v2=1 and v4=1 of the symmetric top molecule, PF3, have been analyzed again. The B0= 7819.9907(13) MHz, DJ= 7.84984(41) kHz, DJk= -11.7644 (11) kHz, HJ= 15.678 (36) mHz, HJk= -66.46 (12) mHz and HkJ= 87.42 (15) mHz have been determined for ground state. The 1=±1 series have been assigned and the rotational parameters including B4=7823.09212(41) MHz, (q+t)4= -29.49200(65) MHz, rt=2.9465 (13) MHz and (Cζ)4= -3010.94684(41) MHz for v4=1 state were determined accurately


2019 ◽  
Author(s):  
Matthew M. Brister ◽  
Carlos Crespo-Hernández

<p></p><p> Damage to RNA from ultraviolet radiation induce chemical modifications to the nucleobases. Unraveling the excited states involved in these reactions is essential, but investigations aimed at understanding the electronic-energy relaxation pathways of the RNA nucleotide uridine 5’-monophosphate (UMP) have not received enough attention. In this Letter, the excited-state dynamics of UMP is investigated in aqueous solution. Excitation at 267 nm results in a trifurcation event that leads to the simultaneous population of the vibrationally-excited ground state, a longlived <sup>1</sup>n<sub>O</sub>π* state, and a receiver triplet state within 200 fs. The receiver state internally convert to the long-lived <sup>3</sup>ππ* state in an ultrafast time scale. The results elucidate the electronic relaxation pathways and clarify earlier transient absorption experiments performed for uracil derivatives in solution. This mechanistic information is important because long-lived nπ* and ππ* excited states of both singlet and triplet multiplicities are thought to lead to the formation of harmful photoproducts.</p><p></p>


2017 ◽  
Vol 19 (30) ◽  
pp. 19590-19600 ◽  
Author(s):  
G. Capano ◽  
T. J. Penfold ◽  
M. Chergui ◽  
I. Tavernelli

On-the-fly excited state molecular dynamics is a valuable method for studying non-equilibrium processes in excited states and is beginning to emerge as a mature approach much like its ground state counterparts.


1974 ◽  
Vol 29 (8) ◽  
pp. 1213-1215 ◽  
Author(s):  
N. W. Larsen ◽  
B. P. Winnewisser

Rotational transitions of 16012C32S and 16013C32S in the ground vibrational state and of 16012C32S in several excited states have been accurately measured in the millimeter wave region for a minimum of four different J values. The analysis of the measured frequencies leads to rotational constants for the following vibrational states: 0 00 0 of 16O13C32S and 0 00 0, 0 1 1c 0, 0 1 1d 0, 0 20 0, 0 22c 0, 0 22d 0, 0 00 1 of 16O12C32S. Since the two components of the 0 22 0 transitions were resolved, an analysis of the l-type resonance was carried out and the interval 0 22 0 - 0 20 0 has been determined to be -4.63(10) cm-1. The result is in good agreement with the presently available determination of this level from vibrational spectra.


1983 ◽  
Vol 38 (12) ◽  
pp. 1309-1319 ◽  
Author(s):  
Yoshiaki Sasada

Abstract The rotational spectra of 3-bromothiophene in the excited states of two vibrational modes were observed and the rotational constants, the centrifugal distortion constants, and the nuclear quadrupole coupling constants were determined. The wave numbers of the two vibrational modes were evaluated to be 210 cm-1 and 320 cm-1 by measuring relative intensities of the ground and excited vibrational transitions. Variations in the inertia defect for each of the vibrational modes are compared with the results of the approximate calculation.


1990 ◽  
Vol 45 (9-10) ◽  
pp. 1165-1168 ◽  
Author(s):  
R. Spiehl ◽  
A. Guarnieri

Abstract The rotational spectra of CHF235Cl and CHF237Cl (CFC22) in the vibrational ground state between 42 and 214 GHz are reported. A centrifugal distortion analysis up to the sixth order is carried out.


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