Terahertz Measurements of Rotational Transitions in Vibrationally Excited States of N2O

Methyl formate (HCOOCH3) is an important interstellar molecule. More than 1000 rotational transitions including those from the ground state, torsionally excited states, and of its isotopologues have been observed towards several astrophysical sources. The laboratory spectra of methyl formate in the microwave spectral region contain many unassigned transitions and many of them are likely to be due to rotational transitions in the low-lying excited states. We report the laboratory identification of new rotational transitions in the COC deformation (ν12) excited state. The identification was made possible by combining the microwave data with rotation–vibration spectra taken in the far-infrared region at the Canadian Light Source synchrotron.

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Terahertz Measurements of Rotational Transitions in Vibrationally Excited States of OCS

Journal of Molecular Spectroscopy ◽

10.1006/jmsp.1999.8046 ◽

2000 ◽

Vol 200 (1) ◽

pp. 145-146 ◽

Cited By ~ 4

Author(s):

I. Morino ◽

K.M.T. Yamada ◽

A.G. Maki

Keyword(s):

Excited States ◽

Vibrationally Excited ◽

Rotational Transitions

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HIGH-RESOLUTION LASER SPECTROSCOPY OF S1-S0 TRANSITION OF NAPHTHALENE: MEASUREMENT OF VIBRATIONALLY EXCITED STATES

Proceedings of the 70th International Symposium on Molecular Spectroscopy ◽

10.15278/isms.2015.fa09 ◽

2015 ◽

Author(s):

Takumi Nakano ◽

Shunji Kasahara ◽

Ryo Yamamoto

Keyword(s):

High Resolution ◽

Excited States ◽

Laser Spectroscopy ◽

Vibrationally Excited

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Excited-State Dynamics in the RNA Nucleotide Uridine 5’-Monophosphate Investigated by Femtosecond Broadband Transient Absorption Spectroscopy

10.26434/chemrxiv.7860023 ◽

2019 ◽

Author(s):

Matthew M. Brister ◽

Carlos Crespo-Hernández

Keyword(s):

Excited State ◽

Excited States ◽

Ground State ◽

Transient Absorption ◽

Electronic Energy ◽

Transient Absorption Spectroscopy ◽

Electronic Relaxation ◽

Vibrationally Excited ◽

Excited State Dynamics ◽

Π State

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 1nOπ* state, and a receiver triplet state within 200 fs. The receiver state internally convert to the long-lived 3ππ* 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.

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The Microwave Spectrum of 3,4-Dihydro-1,2-Pyran

Zeitschrift für Naturforschung A ◽

10.1515/zna-1985-0909 ◽

1985 ◽

Vol 40 (9) ◽

pp. 913-919

Author(s):

Juan Carlos López ◽

José L. Alonso

Keyword(s):

Dipole Moment ◽

Excited States ◽

Ground State ◽

Principal Axis ◽

Microwave Spectrum ◽

Average Intensity ◽

Ring Conformation ◽

Vibrationally Excited ◽

Rotational Constants ◽

Displacement Measurements

Abstract The rotational transitions of 3,4-dihydro-1,2-pyran in the ground state and six vibrationally excited states have been assigned. The rotational constants for the ground state (A = 5198.1847(24), B = 4747.8716(24) and C = 2710.9161(24) have been derived by fitting μa, μb and μc-type transitions. The dipole moment was determined from Stark displacement measurements to be 1.400(8) D with its principal axis components |μa| =1.240(2), |μb| = 0.588(10) and |μc| = 0.278(8) D. A model calculation to reproduce the ground state rotational constants indicates that the data are consistent with a twisted ring conformation. The average intensity ratio gives vibrational separations between the ground and excited states of the ring-bending and ring-twisting modes of ~ 178 and ~ 277 cm-1 respectively.

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