Preface
Nucleation is intrinsically an interfacial phenomenon. Classical nucleation theory is
based on nucleation work of cluster formation that arises from the interfacial free
energy. This feature is compounded in the nucleation of gas hydrates due to their
unique attributes. It is therefore not obvious how best to introduce an enormously
complex subject of nucleation of gas hydrates. The basic approach I ended up
adopting in writing this monograph was the principle of Occam’s razor—keep it as
simple as possible but not simpler. Abinitio considerations were employed where
appropriate to minimize the number of underlying assumptions on which our
subjects are built. Also, effort was made to describe relevant concepts as simple as
possible so that the readers would be able to intuitively grasp the essence of the
conceptual ideas but not so simple that the descriptions would become inaccurate.
Richard Feynman once remarked that he would consider that he has understood an
equation when he could guess its answer without actually solving it.
The first two chapters are of general utility and applicable to nucleation phenomena of any system. Chapter 1 introduces classical nucleation theory and its
underlying conceptual ideas. Chapter 2 details the two leading experimental techniques for investigations of nucleation rates, which should also be of general utility
and applicability to nucleation studies of any system. Nucleation rates are central to
nucleation phenomena of a given system and so is the case for gas hydrates. In fact,
a primary difficulty in the investigation of clathrate hydrate nucleation has been the
inability of the researchers to determine and compare nucleation rates of clathrate
hydrates across various systems of different scales and complexities, which in turn
has been limiting the ability of the researchers to study the nucleation process itself.
Chapter 3 introduces selected physical properties of gas hydrates that are relevant to
nucleation. Chapter 4 then introduces interfacial gaseous states. Heterogeneous
nucleation of gas hydrates requires not only a solid substrate that could lower the
nucleation work and the activation barrier but also ample supplies of guest gases in
its vicinity. This unique attribute of gas hydrate systems renders interfacial gaseous
states the key concept in the heterogeneous nucleation of gas hydrates. Finally,
Chapter 5 introduces nucleation of ice and nucleation of gas hydrates. Since this
monograph is meant to introduce the complex subject of nucleation of gas hydrates,
vii
Nucleation is intrinsically an interfacial phenomenon. Classical nucleation theory is
based on nucleation work of cluster formation that arises from the interfacial free
energy. This feature is compounded in the nucleation of gas hydrates due to their
unique attributes. It is therefore not obvious how best to introduce an enormously
complex subject of nucleation of gas hydrates. The basic approach I ended up
adopting in writing this monograph was the principle of Occam’s razor—keep it as
simple as possible but not simpler. Abinitio considerations were employed where
appropriate to minimize the number of underlying assumptions on which our
subjects are built. Also, effort was made to describe relevant concepts as simple as
possible so that the readers would be able to intuitively grasp the essence of the
conceptual ideas but not so simple that the descriptions would become inaccurate.
Richard Feynman once remarked that he would consider that he has understood an
equation when he could guess its answer without actually solving it.
The first two chapters are of general utility and applicable to nucleation phenomena of any system. Chapter 1 introduces classical nucleation theory and its
underlying conceptual ideas. Chapter 2 details the two leading experimental techniques for investigations of nucleation rates, which should also be of general utility
and applicability to nucleation studies of any system. Nucleation rates are central to
nucleation phenomena of a given system and so is the case for gas hydrates. In fact,
a primary difficulty in the investigation of clathrate hydrate nucleation has been the
inability of the researchers to determine and compare nucleation rates of clathrate
hydrates across various systems of different scales and complexities, which in turn
has been limiting the ability of the researchers to study the nucleation process itself.
Chapter 3 introduces selected physical properties of gas hydrates that are relevant to
nucleation. Chapter 4 then introduces interfacial gaseous states. Heterogeneous
nucleation of gas hydrates requires not only a solid substrate that could lower the
nucleation work and the activation barrier but also ample supplies of guest gases in
its vicinity. This unique attribute of gas hydrate systems renders interfacial gaseous
states the key concept in the heterogeneous nucleation of gas hydrates. Finally,
Chapter 5 introduces nucleation of ice and nucleation of gas hydrates. Since this
monograph is meant to introduce the complex subject of nucleation of gas hydrates,
vii