Infrared spectra of cis and trans-(NO)2− anions in solid argon

Abstract

Laser-ablation of over 20 different metal targets with concurrent 10 K codeposition of Ar/NO mixtures produces metal independent infrared bands at 1589.3 cm−1 due to (NO)2+, a new absorption at 1221.0 cm−1, and a band set at 1300.3, 1222.7, 884.4 cm−1. The latter bands decrease more on annealing than the 1221.0 cm−1 band. Isotopic substitution (14NO,15NO, 15N18O, and mixtures) shows that these new vibrations involve two equivalent N–O oscillators, which identifies two new (NO)2 species. The excellent agreement with frequencies, intensities, and isotopic frequency ratios from density functional theory calculations substantiates assignment of the 1221.0 cm−1 band to trans-(NO)2− and the three band set to cis-(NO)2−. The observation of a weak combination band at 2492.0 cm−1 further substantiates assignment of the two N–O stretching modes in cis-(NO)2−.

Multiconfiguration SCF electric field gradients in (NO)2 and its singly charged ions

“…The vibrational frequencies compared in Table 2 to those from density functional theory calculations [5] show discrepancies to be expected for given type of approaches.…”

“…An extensive view of the earlier work on various aspects of the behavior of these dimer species can be found, for example, in the introductions of [1,2], as well as in recent papers dealing separately with the neutral [3], cationic [4] and anionic forms [5]. The NO dimer has also been studied by a number of spectroscopic techniques including those producing microwave transitions [6][7][8].…”

The infrared spectroscopy and photochemistry of NO3 trapped in solid neon

“…Many uncharged and ionic products contributed to the product spectrum, which is summarized in the first column of 38 and ionic products derived from NO included NO + , 37 as well as trans-ONNO + and trans-ONNO − . 30,39 The presence of NO 2 led to the appearance of absorptions of NO 2 − and NO 3 − . 35 A very sharp, unstructured absorption at 762.9 cm −1 lies very close to the 762.33 cm −1 gas-phase band center determined by Friedl and Sander 17 for the 2 fundamental of NO 3 , and a prominent absorption at 1491.4 cm −1 with a weaker companion at 1492.7 cm −1 lies close to the gas-phase band center of the absorption heretofore assigned [16][17][18] to the 3 fundamental of NO 3 .…”

The puzzling infrared spectra of the nitric oxide dimer radical cation: a systematic application of Brueckner methods

“…Since 1990, the NO dimer and its ionic counterparts have been extensively studied at several experimental laboratories [1± 9], but assignments for the infrared spectrum are still controversial (table 1). For example, the prominent infrared absorption 1619 (or 1618) cm ¡1 has been assigned [2] aş 5 corresponding to the asymmetric N± O stretching vibrational mode of the trans anionic ONNO ¡ , assigned to the trans ONNO ‡ cation [4,7], and assigned to the cis ONNO ‡ [8,9]. The experimental frequencies of other modes are not conclusively identi® ed either (see table 1).…”