title l.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Title PowerPoint Presentation
Download Presentation
Title

Loading in 2 Seconds...

play fullscreen
1 / 22

Title - PowerPoint PPT Presentation


  • 398 Views
  • Uploaded on

Title. Electronic Spectra and Structures of Solvated NH 4 Radicals, NH 4 (NH 3 ) n ( n = 1 - 8). Shinji Nonose a) , Tomokazu Taguchi a) , Feiwu Chen b,c) , Suehiro Iwata c,d) , and Kiyokazu Fuke a) a) Department of Chemistry, Faculty of Science, Kobe University, Kobe 657-8501, Japan

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Title' - Jims


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
title
Title

Electronic Spectra and Structures of Solvated NH4 Radicals, NH4(NH3)n (n = 1 - 8)

Shinji Nonose a), Tomokazu Taguchi a), Feiwu Chen b,c) , Suehiro Iwatac,d), and Kiyokazu Fuke a)

a)Department of Chemistry, Faculty of Science, Kobe University, Kobe 657-8501, Japan

b)Japan Science and Technology Corporation, Japan

c) Institute of Molecular Science, Okazaki 444-8585, Japan

d)Evaluation of University Education and Research, NIAD, Chiyoda, Tokyo, 101-8436, Japan

abstract
Abstract

NH4(NH3)nproduced through the photolysis of ammonia clusters

Photodepletion spectroscopy of NH4(NH3)n

derived from 3p-3s excitation of NH4

1. Vibrationaly resolved spectrum of NH4NH3

(9000 - 12000 cm-1)

2. Electronic spectra of NH4(NH3)n(n = 1 - 8)

(4500 - 16000 cm-1 )

schematic of set up for dual beam configuration
Schematic of Set up for Dual Beam Configuration

(NH3)n  NH4(NH3)m +NH2 +(n-m-2)NH3

nh 4 nh 3 n mass spectrum
NH4(NH3)n Mass Spectrum

NH4(NH3)n Mass Spectrum

Relative Intensity

Flight time

absorption spectra of nh 4 nh 3 at various delay time between n 1 and n 2
Absorption Spectra of NH4NH3 at Various Delay Time between n1 and n2

Absorption Cross Section(a. u.)

Wavenumber / 1000 cm-1

absorption spectrum of nh 4 nh 3 9000 12000 cm 1
Absorption Spectrum of NH4NH3 (9000 - 12000 cm-1)

Absorption Cross Section(a. u.)

0

500

1000

1500

2000

Wavenumber / cm-1

adiabatic energy diagram of nh 4 and nh 4 nh 3
Adiabatic Energy Diagram of NH4 and NH4NH3

Electronic Character of 3p States of NH4NH3

3p() state, 12E

3p() state, 22A

assignment of absorption spectrum of nh 4 nh 3 9000 12000 cm 1
Assignment of Absorption Spectrum of NH4NH3 (9000 - 12000 cm-1)

Absorption Cross Section(a. u.)

0

500

1000

1500

2000

Wavenumber / cm-1

absorption spectra of nh 4 nh 3 n n 1 8 4500 16000 cm 1
Absorption Spectra of NH4(NH3 ) n (n = 1 - 8) (4500 - 16000 cm-1)

Absorption Cross Section(a. u.)

Wavenumber / 1000 cm-1

intermolecular potential curves of nh 4 nh 3
Intermolecular PotentialCurves of NH4NH3

Determination of the successive binding energies Dn-1,n[NH4(NH3)n-1 - NH3]

Energy (eV)

J. D. Payzant, A. J. Cunnungham, P. Kebarle, Can. J. Chem., 51, 3242 (1973).

K. Fuke, R. Takasu, F. Misaizu, Chem. Phys. Lett., 229, 597 (1994).

NH4-NH3Distance

successive binding energies of nh 4 nh 3 n
Successive Binding Energies of NH4(NH3)n

Binding Energy (eV)

Cluster Size

summary
Summary
  • 1. Vibronic Spectrum of NH4NH3
  • Band Origin of 22A State 9305 cm-1
  • Band Origin of 12E State 10073 cm-1
    • Excitation of Intermolecular Bending Vibrations
  • 2. Electronic Absorption Spectra of NH4(NH3)n(n = 1-8)
  • 3p-3s Transition of NH4
  • First Solvation Shell Closing at NH4(NH3)4
  • Spontaneous Ionization of NH4 in Clusters
table 3 band positions in 2 2 a 1 2 a and 1 2 e 1 2 a transition of nh 4 nh 3
Table 3. band positions in 22A – 12A and 12E – 12A transition of NH4NH3

Band Positions in 22A – 12A and 12E – 12A

Transition of NH4NH3

abstract org
Abstract.org

Abstract

Electronic spectra of ammoniated ammonium radicals, NH4(NH3)n,produced through the photolysis of ammonia clusters, are investigated with a laser photodepletion spectroscopy.Vibrationaly resolved bands beginning at energy of 9305 ± 15 cm-1 are successfully assigned to NH4NH3. These bands are ascribed to the 2 2A —1 2A transition derived from the 3p2F2-3s2A1 excitation of NH4. A second group of bands beginning at energy 10073 ± 15 cm-1 is assigned to the 12E -12A transition. Electronic spectra of a series of NH4(NH3)n(n = 1 - 8) are also recorded with low resolution in the energy region of 4500 - 16000 cm-1. A drastic decrease of the excitation energy from 15062 cm-1 for NH4 to 5800 cm-1 for NH4(NH3)4 is observed, while no appreciable spectral change is found for n  5. The large spectral change is ascribed to the spontaneous ionization of NH4 in ammonia clusters. Successive binding energies of NH4(NH3)nin the excited state are determined from the spectral band positions.

vibrational frequency cm 1
Vibrational frequency (cm-1)

NH3 symmetric stretching A1 3337

symmetric bending A1 950

asymmetric stretching E 3444

symmetric bending A1 1627

NH4+ symmetric stretching A1 3042

bending E 1711

asymmetric stretching F2 3135

bending F2 1403

NH4 symmetric stretching A1 2552

bending E 1581

G. Herzberg, J. Astrophys., 5, 131 (1984).

electronic character of 3 p states of nh 4 nh 3
Electronic Character of 3p States of NH4NH3

3p() state, 12E

3p() state, 22A