Diode laser detection of the bending mode of HCO+

Abstract

The infrared laser absorption spectrum of the bending fundamental of HCO+ has been detected using the velocity modulation technique. Assignment and measurement of 23 transitions yields a band center of 829.721(2) cm−1.

Anharmonic vibrational frequencies and vibrationally-averaged structures of key species in hydrocarbon combustion: HCO+, HCO, HNO, HOO, HOO–, CH3 +, and CH3

“…Klemperer's computational assignment was supported theoretically [63] and subsequently confirmed experimentally [64]. Its rotational and vibrational transitions have been thoroughly characterized by microwave [65][66][67][68][69][70][71][72][73] and infrared laser spectroscopy [74][75][76][77][78][79][80][81][82][83]. There have been many computational studies on the structure, PES [84][85][86][87][88][89], and rovibrational spectra [90][91][92][93] of HCO þ .…”

Submillimeter-wave spectroscopy of HCO+ in the excited vibrational states

“…It is interesting to note that he detected the lines in (02 2 0) as well as those in (03 1 0) and (03 3 0) that were not observed by Hirota and Endo [11]. The observed (02 2 0) lines were weaker by several times than expected, and the J = 3-2 transitions of (02 2 0) [13][14][15][16][17][18][19][20] and photoionization spectroscopy [21,22]. The states given in broken line specify unmeasured levels whose term values were calculated from the parameters determined by Neese et al [20].…”

“…For the analysis of the second bending excited states and higher, the energy separation between different '-sublevels is better to be known, because the '-type doubling constant q and the energy difference cannot be determined independently. However, in spite of a large number of infrared studies [13][14][15][16][17][18][19][20], no transitions involving the (0 2 0), (0 3 0), and (0 4 0) states have been observed except for the (1 2 0)-(0 2 0) band by Neese et al [20]. It appears that the separation between the ' ¼ 2 and ' ¼ 0 sublevels has been determined only by photoionization spectroscopy by Grant group [21,22].…”

“…The band origins for all three fundamental vibrational bands of HCO + , m 1 C-H stretch, m 2 H-C-O bend, and m 3 C-O stretch, have been determined to be 3088.7 cm À1 [13,14], 829.7 cm À1 [15,16], and 2183.9 cm À1 [17,18], respectively. More extensive work to investigate the hot bands in the m 1 and m 3 band regions was carried out by Liu et al [19] and recently the measurements were extended by Neese et al [20].…”

Multiresonant Spectroscopy and the High-Resolution Threshold Photoionization of Combustion Free Radicals

“…[15][16][17][18] It is the first polyatomic cation to be characterized by application of infrared and microwave absorption spectroscopies. [19][20][21][22][23][24][25][26][27][28] This system continues to serve as a prominent point of contact between experiment and ab initio theories of molecular electronic structure. [29][30][31][32][33] However, despite this fundamental importance and the great deal of experimental work that had been carried out on HCO + over the last 25 years, laboratory measurements had securely determined spectroscopic parameters only for the ground state and three fundamental vibrationally excited states of this system.…”