CHEM01200604005 A. K. Pathak - Homi Bhabha National Institute

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halogen atoms (Cl, Br or I) through O site and the other H 2 O is connected to X 2 via H atom without any inter water H bonding. Structures of the most stable configurations of tri-hydrated cluster of Cl 2 , Br 2 and I 2 are very similar in nature and are displayed in Fig. 4.1 as IIIA, IIIB and III-C, respectively. Two solvent water molecules are in close proximity and connected by H-bonds in these tri-hydrate clusters. The initial guess structures were considered where all the three solvent H 2 O units were directly linked to halogen atoms. In case of tetra-hydrated cluster, planar cyclic H-bonded structures (see Fig.4.1 IVA, IVB and IVC) are obtained as the most stable geometries. One can see that only two solvent water molecules are directly connected to the halogen atoms and the remaining two acts as both H-bond donor and acceptor in this minimum energy structure. In case of penta-hydrated clusters, the most favored structures are also planar where H atom of one H 2 O is approached to one halogen (Cl, Br or I) atom and O atom of another H 2 O is approached to other halogen atom and both these H 2 O units are linked with two other solvent H 2 O molecules via H-bond. The fifth solvent unit is connected to the halogen atom (which is already connected by a H 2 O unit through H atom) through its O atom in case of Cl 2 .5H 2 O, Br 2 .5H 2 O systems and through one of its H atoms in I 2 .5H 2 O system as shown in Fig. 4.1 (VA, VB and VC). It is to be noted that in all these three cases the initial structure for optimization was similar. The most stable structure for hexahydrated cluster, Cl 2 .6H 2 O is calculated to have a surface structure with a three dimensional water network formed by six H 2 O molecules via inter water H-bonding as displayed in Fig. 4.1-VIA. The minimum energy structure of Br 2 .6H 2 O and I 2 .6H 2 O cluster (see Fig.4.1-VIB and 1-VIC) is similar to that of Cl 2 .6H 2 O cluster. In case of hepta-hydrated cluster, Cl 2 system behaves in a different manner compared to that of Br 2 72
and I 2 systems. The most stable structures of Cl 2 .7H 2 O, Br 2 .7H 2 O and I 2 .7H 2 O are shown in Fig. 4.1-(VIIA, VIIB and VIIC). In Cl 2 .7H 2 O cluster, the solvent water units are separated from Cl 2 moiety by a distance of ~ 4.0 Å. The most favoured structure of Br 2 .7H 2 O is the one where the three dimensional network surrounds only one Br atom (see Fig. 4.1-VIIB). On the other hand, the most stable structure of I 2 .7H 2 O cluster is the one where I 2 unit is surrounded by cyclic three dimensional water network formed by seven H 2 O molecules via inter water H-bond as shown in Fig.4.1-VIIC. All H 2 O molecules act as both H-bond donor and acceptor in this hepta-hydrated cluster except two, which were directly attached to the I 2 moiety. The most stable structure of Cl 2 .8H 2 O cluster is displayed in Fig. 4.1-VIIIA. It is clearly seen that Cl 2 moiety is directly attached to only one water molecule as the monohydrated system, Cl 2 .H 2 O and staying away (> 4 Å ) from the seven member water network. The most stable structure of Br 2 .8H 2 O cluster (see Fig. 4.1-VIIIB) is rather different from that of Br 2 .7H 2 O cluster (see Fig. 4.1-VIIB). In the present case, all water molecules act simultaneously as hydrogen bond donor and accepter except the water molecule which is directly attached to the bromine moiety by H-end. Minimum energy structure of I 2 .8H 2 O cluster is very similar to the same from hepta- hydrated cluster, I 2 .7H 2 O. All eight water molecules form a cyclic network, which is connected to iodine molecule from one side of I 2 making a surface structure as shown in Fig.4.1-VIIIC. All X 2 .nH 2 O (X=Cl, Br & I; n=1-8) clusters are stabilized by X…O, X…H and inter water hydrogen bonding interactions. The inter water hydrogen bonding energy (~6- 7 kcal/mol) is greater than the both X…O and X…H interaction energy (~3-5 kcal/mol). Thus, the larger clusters prefer to form strong inter water hydrogen bonded network. 73
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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
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eported experimental findings. Theo
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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 and 98: these systems, X. nH 2 O (X= Br 2
Page 99 and 100: CHAPTER 4 Solubility of Halogen Gas
Page 101: including polarized and diffuse fun
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
Page 149 and 150: symmetric C-O stretching mode of CO
Page 151 and 152: 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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