CHEM01200604005 A. K. Pathak - Homi Bhabha National Institute

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density functional, namely, Becke’s half-and-half (BHH) exchange and Lee-Yang-Parr (LYP) correlation functional (BHHLYP). Split valence basis set with diffusion and double polarization functions on all the atoms, 6-311++G(2d,2p) has been used in all calculations. Pseudo Newton Raphson based algorithm has been applied to look for the minimum energy structures for each K.nNH 3 cluster. The major concern in this algorithm is to guess a good starting geometry of the cluster, which might converge during the calculation to a local or the global minimum. In the present calculation, several possible starting geometries are generated based on different possible three-dimensional structures. Hessian calculations have been performed to check the nature of the optimized structures, to calculate thermodynamic parameters and to generate IR spectrum of the clusters. In a number of cases, first hand optimized minimum energy structures of these open shell systems have yielded one or more normal modes having imaginary frequency. In these cases, the structures have been reoptimized focusing attention on these normal modes till the structures generate no imaginary frequency. Population of the minimum energy configurations of each size clusters has been calculated based on free energy change (ΔG) at 150 K following Boltzmann population distribution. 6.3. Results and Discussion 6.3.1. Structure Only one stable minimum energy structure is obtained through full geometry optimizations of small size (n=1-3) K.nNH3 clusters. It is to be noted that the geometries of clusters having different orientations of N atoms from NH 3 molecule with respect to K atom are considered as the initial guess structures in the present study and only the most 96
stable minimum energy structure is taken from different optimized configurations with small difference in dangling hydrogen orientations. All the stable configurations that are found for each size K.nNH 3 cluster are displayed in Fig. 6.1. The minimum energy structure of mono-ammoniated potassium cluster, K.NH 3 is shown in Fig. 6.1-I. It is clearly seen that N atom of NH 3 is directed towards the K atom and it is ~2.8 Å apart from the metal atom. It is worth to mention that two initial guess structures are considered for geometry optimization. In one case, the N atom of NH 3 is directed towards K atom and in the other case H atoms of NH 3 face towards the metal atom. Full geometry optimization generates exactly the same structure as shown in Fig. 6.1-I. Thus for the larger clusters, the initial thought structure is made where the N atom of NH 3 is oriented towards K atom. Only one minimum energy structure is predicted for di-ammoniated cluster, K.2NH 3 with ∠NKN of 180ºand the optimized structure is displayed in Fig. 6.1- II. Several initial guess structures are considered for the tri-ammoniated clusters, K.3NH 3 based on the minimum energy structure of K.2NH 3 . But only one stable minimum energy structure displayed in Fig. 6.1-III is predicted having ∠NKN = 120º. In all these cases N and K atoms are in same plane. Two minimum energy structures are obtained for K.4NH 3 cluster and shown in Fig.6.1-IVA and IVB, respectively. The most stable structure (see Fig. 6.1-IVA) is a distorted tetrahedral with four N atoms in the corners keeping K atom at the center and more stable than structure IVB having square planar arrangement with four N atoms at the corners by 1.09 kcal/mol. Based on these minimum energy structures, initial guess structures for K.5NH 3 and K.6NH 3 are modeled. In each case, three stable minimum energy structures are found and displayed in Fig. 6.1-VA-VC and Fig.6.1-VIA- VIC, respectively. The most stable conformer of K.5NH 3 cluster is displayed in figure 97
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MICROSOLVATION OF CHARGED AND NEUTR
Page 3 and 4:
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,
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anions (Cl •− 2 , Br •− 2 &
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geometrical parameters close to MP2
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symmetrical DHB, SHB or WHB arrange
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of I-I axis and having the least I-
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Br •− 2 .nH 2 O hydrated cluste
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VI-F VI-G VII-A VII-B VII-C VII-D V
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To see the effect of hydration on t
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Five minimum energy structures disp
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arrangements. In total, it has one
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NO 3 − .nH2 O (n ≥ 6), a few eq
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V-E V-F V-G V-H V-I VI-A VI-B VI-C
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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 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: ammonia. 61-62 Hydrogen bonded wate
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
Page 153 and 154: CHAPTER 8 A Generalized Microscopic
Page 155 and 156: possible breakdown of these laws ma
Page 157 and 158: P 7 P , , P , ,, 1 ∂ 2
Page 159 and 160: M DE = (r, ω)C DE , (r,
Page 161 and 162: known. However, for most of the com
Page 163 and 164: The calculated bulk detachment ener
Page 165 and 166: espect to experimentally measured v
Page 167 and 168: References 1. Ohtaki, H.; Radani, T
Page 169 and 170: 29. Turi, L.; Sheu, W.; Rossky,P.J.
Page 171 and 172: 61. (a) Ehrler, O. T.; Neumark, D.
Page 173 and 174: LIST OF PUBLICATIONS *1. “σ/σ
Page 175 and 176: 13. “Vibrational analysis of I
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CHEM01200604005 A. K. Pathak - Homi Bhabha National Institute

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