CHEM01200604005 A. K. Pathak - Homi Bhabha National Institute

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mode compared to the free water mode. But stretching mode of X. nH 2 O (X= Cl •− 2 , Br •− 2 , I •− 2 , CO •− − 3 & NO 3 ) clusters always remains far beyond of 3000 cm -1 2− except CO 3 system, where at least one stretching mode appeared below 3000 cm -1 . On the other hand the bending mode of water molecule remains unaffected in all the cases. 3.4. Conclusions The IR spectra of Cl •− 2 .nH 2 O (n=1-5) clusters are studied at BHHLYP/6- 311++G(d,p) level of theory. It is observed that the hydrated clusters are stabilized by double hydrogen bonding (DHB), single hydrogen bonding (SHB) and inter water hydrogen bonding (WHB). Due to these interactions, bands due to stretching (O-H) hydrated clusters get shifted compared to that of the free water molecule. The IR spectra of Cl •− 2 .nH 2 O (n=1-5) clusters is characterized by large shift of O-H (~300 cm -1 ) stretching mode compared to the free water mode. But stretching mode remains always far beyond of 3000 cm -1 . On the other hand, the bending mode of water molecule remains unaffected. This observation is also true for other systems (Br •− 2 , I •− 2 , CO •− 3 and NO − 3 ) except CO 2− 3 system, where at least one stretching mode appears below 3000 cm -1 . It is observed that the FT-DACF IR spectrum is far off from the experimentally reported spectrum. On other hand an excellent agreement of weighted average scaled IR spectrum of Cl •− 2 .nH 2 O (n=3-5) clusters at 100K with experimentally measured spectrum is observed. 68
CHAPTER 4 Solubility of Halogen Gases in Water 4.1. Introduction Molecular cluster acts as an intermediate state between isolated gaseous molecule and condensed phase bulk system. It is well known that in solution (bulk) many important properties of neutral and charged chemical species are often widely different from that in the isolated gas phase. The structure and energetics of the cluster of a chemical species may be different from both the gas phase as well as the bulk. Bulk properties of a solute in solution result from the combined effect of solute-solvent and solvent-solvent interactions. It cannot be obtained from the properties of the isolated solute species alone. Several efforts are being made to connect molecular cluster properties of a chemical species to its bulk properties. 9,33-35 Halogen molecules, X 2 (X=Cl, Br & I) provided one of the early model systems for understanding solvent effects on molecular spectra because they are apparently simple molecules whose spectral bands shift substantially in different solvents. The halogens also act as a popular model system for studying nearest neighbour effects on spectroscopy with the advent of molecular beam studies of dimers and small clusters. However, a very little effort has been put to study microhydration of X 2 (X=Cl & Br) systems. 55-57 The molecular interaction between a neutral solute and solvent water molecules as well as the hydrogen bonding interactions among the solvent water 69
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MICROSOLVATION OF CHARGED AND NEUTR
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STATEMENT BY AUTHOR This dissertati
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Dedicated to my Daughter, Wife and
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CONTENTS Page No. SYNOPSIS LIST OF
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CHAPTER 4 Solubility of Halogen Gas
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7.3.4. IR and Raman Spectra 117-121
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S Macroscopic Microscopic Dual leve
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molecular level interaction during
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Chapter 3: This chapter describes I
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In this system the conformers of a
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LIST OF FIGURES Page No. Fig. 1.1 2
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Fig. 2.6 54 (I) Plot of calculated
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(IIIA) Cl 2 .3H 2 O; (IIIB) Br 2 .3
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Fig. 6.3 104-105 Calculated scaled
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LIST OF TABLES Page No. Table. 2.1
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CHAPTER 1 Introduction 1.1. Microso
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1.2. Motivation 1.2.1. Macrosolvati
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ulk water and pure neutral water cl
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insight about the electronic struct
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Newton -Raphson (NR) method expand
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potential energy surface for these
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terms, the energy can be written in
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Boyd proposed the use of Gaussian t
Page 47 and 48: eported experimental findings. Theo
Page 49 and 50: hydrated halide series, X¯.nH 2 O,
Page 51 and 52: anions (Cl •− 2 , Br •− 2 &
Page 53 and 54: geometrical parameters close to MP2
Page 55 and 56: symmetrical DHB, SHB or WHB arrange
Page 57 and 58: of I-I axis and having the least I-
Page 59 and 60: Br •− 2 .nH 2 O hydrated cluste
Page 61 and 62: VI-F VI-G VII-A VII-B VII-C VII-D V
Page 63 and 64: To see the effect of hydration on t
Page 65 and 66: Five minimum energy structures disp
Page 67 and 68: arrangements. In total, it has one
Page 69 and 70: NO 3 − .nH2 O (n ≥ 6), a few eq
Page 71 and 72: V-E V-F V-G V-H V-I VI-A VI-B VI-C
Page 73 and 74: VII-D VII-E VII-F VII-G VII-H VII-I
Page 75 and 76: VIII-K VIII-L Fig.2.2. Fully optimi
Page 77 and 78: clusters. Hydrated cluster having c
Page 79 and 80: However, these calculations do not
Page 81 and 82: Table 2.1. Weighted average energy
Page 83 and 84: Where, E[I •− 2 .nH 2 O] is the
Page 85 and 86: The variation of the weighted avera
Page 87 and 88: CHAPTER 3 IR Spectra of Water Embed
Page 89 and 90: ecome more meaningful. At present,
Page 91 and 92: I-A II-A II-B III-A III-B III-C III
Page 93 and 94: Cluster experiments are carried out
Page 95 and 96: 3350-3500 cm -1 (scaling factor ~0.
Page 97: these systems, X. nH 2 O (X= Br 2
Page 101 and 102: including polarized and diffuse fun
Page 103 and 104: and I 2 systems. The most stable st
Page 105 and 106: Cl Cl Br Br I I VA VB VC Cl Cl Br B
Page 107 and 108: (Br δ+ -Br δ- ) in the studied hy
Page 109 and 110: stabilization energy does not follo
Page 111 and 112: 80 Cl 2 .nH 2 O (n=1-8) 80 Br 2 .nH
Page 113 and 114: separated ion pair in presence of s
Page 115 and 116: adical ( • OH) reacts with HCO 3
Page 117 and 118: most stable conformer for each size
Page 119 and 120: The structures of the hydrated clus
Page 121 and 122: Table 5.1. Calculated absorption ma
Page 123 and 124: molar extinction coefficient value
Page 125 and 126: ammonia. 61-62 Hydrogen bonded wate
Page 127 and 128: stable minimum energy structure is
Page 129 and 130: IV-A IV-B V-A V-B V-C VI-A VI-B VI-
Page 131 and 132: 6.3.3. Vertical Ionization Potentia
Page 133 and 134: 311++G(2d,2p) level, the scaling fa
Page 135 and 136: K(NH 3 ) 4 K(NH 3 ) 5 IR Intensity
Page 137 and 138: CHAPTER 7 Structure, Energetics and
Page 139 and 140: Thus Monte Carlo based simulated an
Page 141 and 142: I I I I I I I I A B C D I I I I I I
Page 143 and 144: interaction as well as solvent-solv
Page 145 and 146: Table 7.1. Various energy parameter
Page 147 and 148: change in VDE is observed. This is
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symmetric C-O stretching mode of CO
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to the maximum charge transfer of t
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CHAPTER 8 A Generalized Microscopic
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possible breakdown of these laws ma
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P 7 P , , P , ,, 1 ∂ 2
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M DE = (r, ω)C DE , (r,
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known. However, for most of the com
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The calculated bulk detachment ener
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espect to experimentally measured v
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References 1. Ohtaki, H.; Radani, T
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29. Turi, L.; Sheu, W.; Rossky,P.J.
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61. (a) Ehrler, O. T.; Neumark, D.
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LIST OF PUBLICATIONS *1. “σ/σ
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13. “Vibrational analysis of I
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CHEM01200604005 A. K. Pathak - Homi Bhabha National Institute

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