Photodissociation of highly vibrationally excited NH3 in the 5νN–H region: Initial vibrational state dependence of N–H bond dissociation cross section

Abstract

The weak hydrogen bond in the fluorobenzene-ammonia van der Waals complex: Insights into the effects of electron withdrawing substituents on π versus in-plane bonding Selective OD bond dissociation of HOD: Photodissociation of vibrationally excited HOD in the 5 ν O D state Ab initio potential energy surfaces, total absorption cross sections, and product quantum state distributions for the low-lying electronic states of N 2 O J. Chem. Phys. 122, 054305 (2005); 10.1063/1.1830436Bond-selective photodissociation of partially deuterated ammonia molecules: Photodissociations of vibrationally excited NHD 2 in the 5ν NH state and NH 2 D in the 5ν ND state Ultraviolet photolysis of highly vibrationally excited NH 3 (X 1 A 1 Ј) in the 5 N-H band has been studied using a crossed laser and molecular beams method. Relative cross sections of N-H bond dissociation via the à ←X transition have been determined by the measurement of the action spectrum, utilizing a ͑2ϩ1͒ resonance enhanced multiphoton ionization scheme of product H atoms. The obtained cross section for the photolysis of the 4 1 ϩ 3 state ͑4 quanta in the symmetric stretching and 1 quantum in the antisymmetric stretching͒ was 1.23Ϯ0.06 times as large as that of the 5 1 state. To interpret the ratio of the obtained cross sections, we have evaluated the Franck-Condon factors for these vibrational states, by utilizing time-dependent wave-packet calculations on the potential energy surfaces constructed by an ab initio molecular orbital procedure.

The 5νNH and 5νND vibrational bands of partially deuterated ammonia species

“…4. For the pure NH 3 sample, the 5m NH band reported in [3,15,22,23] is well reproduced, as shown in Fig. 4A.…”

“…Since the experimental procedure is similar to the previous one [3], the experimental apparatus and procedure are described briefly. A homemade PA cell was filled with each gas sample at the pressure of 20-100 Torr, and the laser beam for the overtone excitation was introduced into the PA cell.…”

“…Thus, we used mixtures of NH 3 and ND 3 with various mixing ratio to prepare equilibrated mixtures with different compositions of NH 2 D and NHD 2 , which were determined by the initial mixing ratio. Three types of gas mixtures containing NH 2 D and NHD 2 were prepared by mixing NH 3 (Nippon-Sanso 99.999%) and ND 3 (Isotec 99.38 atom%) at the ratios of 3:1, 1:1, and 1:3 (hereafter cited as 25, 50, and 75% deuterated samples, respectively).…”

“…After the pioneering work by CrimÕs and RosenwaksÕ groups for the HOD molecule [1,2], we recently investigated VMP of NH 3 [3], NH 2 D, and NHD 2 [4]. In comparison with HOD and NH 3 , the spectroscopic information was quite limited for NH 2 D and NHD 2 .…”

Optical emission in the dissociation of ammonia by low energy He+ ions

“…More recent studies [16,17] used synchrotron radiation or other modern VUV sources. Spectroscopic control of dissociation by pumping vibrational modes with microwave photons was demonstrated in references [18][19][20].…”