The vibrational and electronic spectra of 3,4-dimethylenecyclobutene

1972 ◽  
Vol 25 (2) ◽  
pp. 241 ◽  
Author(s):  
DWT Griffith ◽  
JE Kent ◽  
MF O'Dwyer

The infrared spectrum of 3,4-dimethylenecyclobutene (dmcb) as a vapour, glass, and polycrystalline film has been investigated from 4000 to 250 cm-1. The Raman spectrum of liquid dmcb and the infrared spectrum of 1,2-dideutero-3,4-dimethylenecyclobutene vapour have also been investigated. On the basis of these results a partial assignment of the spectrum has been made. A study of the electronic spectrum of dmcb from the visible to the vacuum ultraviolet at 169 nm has also been undertaken and the spectrum has been found to be very diffuse in all bands. Assignments are discussed in the light of theoretical calculations.

1970 ◽  
Vol 48 (14) ◽  
pp. 1664-1674 ◽  
Author(s):  
D. W. Lepard

This paper presents a method for calculating the relative intensities and Raman shifts of the rotational structure in electronic Raman spectra of diatomic molecules. The method is exact in the sense that the wave functions used for the calculations may belong to any intermediate case of Hund's coupling schemes. Using this method, theoretical calculations of the pure rotational and electronic Raman spectrum of NO, and the pure rotational Raman spectrum of O2, are presented. Although a calculated stick spectrum for NO was previously shown by Fast et al., the details of this calculation are given here for the first time.


2021 ◽  
Vol 23 (38) ◽  
pp. 22096-22102
Author(s):  
Zuoying Wen ◽  
Xiaoxiao Lin ◽  
Xiaofeng Tang ◽  
Bo Long ◽  
Chengcheng Wang ◽  
...  

C2H5O2 plus its gauche and trans conformers are studied using synchrotron-based VUV photoionization mass spectrometry and theoretical calculations, and it is found that the gauche conformer has favorable Franck–Condon factors in photoionization.


1974 ◽  
Vol 52 (18) ◽  
pp. 3149-3157 ◽  
Author(s):  
Herbert F. Shurvell ◽  
Shiv C. Dass ◽  
Robert D. Gordon

The infrared spectrum of gaseous CF3NO has been studied in the region 4000–35 cm−1. The infrared spectrum of the condensed phase has also been recorded and a complete vibrational assignment is proposed. Attempts to record the Raman spectrum have been hampered by photolysis. A frequency of 50 cm−1 for the CF3 torsional mode has been estimated from combination and hot bands. This corresponds to a barrier to internal rotation of approximately 425 cal/mol (150 cm−1). A normal coordinate analysis has been carried out and potential energy distributions, and valence and symmetry force constants are reported.


1954 ◽  
Vol 32 (10) ◽  
pp. 630-634 ◽  
Author(s):  
B. P. Stoicheff

The pure rotational spectrum and the Q branch of the 1–0 band of N2 were photographed in the second order of a 21 ft. grating. An analysis of the rotational spectrum yields the rotational constants[Formula: see text]The value of B0 together with the Bν values obtained from the electronic bands of N2 gives[Formula: see text]Revised values of the vibrational constants have also been calculated using the results of the present work and the published data on the electronic spectra.


1970 ◽  
Vol 48 (4) ◽  
pp. 607-614 ◽  
Author(s):  
Hans R. Wyss ◽  
Michael Falk

The molar absorptivity of dilute HDO in water and in aqueous NaCl solutions was determined at temperatures between 10 and 85° in the spectral region from 4000 to 2000 cm−1.The infrared band profiles for the OH and OD stretching fundamentals are single-peaked and devoid of shoulders, in contrast to the high-frequency shoulders recently observed in the Raman spectrum. It is shown that such shoulders do not contradict a single-peaked distribution of OH oscillators with respect to inter-molecular geometry. Absence of resolvable sub-bands in the spectrum of HDO in concentrated salt solutions indicates a wide distribution of ion–H2O interactions, akin to the distribution of H2O–H2O interactions in water.


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