Contents



**Compounds at Molecular Level: A Theoretical Approach 105** Pham Ngoc Khanh and Nguyen Tien Trung


Lingyun Yang, Peter J. H. Scott and Xia Shao


Preface

land usage.

and tidal energy.

Carbon dioxide (CO2) is an ancient molecule that is constantly inducing next generations of urgent yet innovative research. CO2 is a stable and relatively inert triatomic molecule that exists as a gas at ambient temperature and pressure. It is generated naturally from various sources such as forest fires, volcanic eruptions, and respiration of living organisms. The pho‐ tosynthesis of plants and other autotrophs play an indispensable role in balancing the car‐ bon/oxygen cycle and, consequently, in maintaining the life on earth. The global concentration of CO2 in the atmosphere was approximately 270 ppm by volume prior to the industrial revolution. Nowadays, the carbon dioxide level has reached up to 405 ppm, ap‐ proximately a 50% increase. This steady increase in CO2 emissions stems from the large con‐ sumption of fossil fuels and anthropogenic activity in addition to the wide deforestation for

Pollution is regarded as the issue of our era, since dominant industries deem its control as an expense that overwhelms the domains that are beneficial to the advances of science. Find‐ ing alternatives to indispensable fields such as providing energy, food, drugs, and dyes for medicinal probes, among others, seems to conflict with the innovative progress reported ev‐ ery day in academia and industry. The greenhouse effect is one of the utmost contemporary issues in this regard. Carbon dioxide is currently the most abundant greenhouse gas (GHG). CO2 plays a detrimental role in preventing the heat loss and protecting the life on earth dur‐ ing nighttime. However, the increased concentrations of GHGs, particularly CO2, are be‐

Several international conventions and governmental protocols have been formulated to re‐ duce the CO2 emissions, such as the *Kyoto Protocol*, the *UN Framework Convention on Climate Change*, and the *Intergovernmental Panel on Climate Change*. To date, there is no universal agreement on these laws, and many countries and industries do not abide by these conven‐ tions. Therefore, immediate actions and solutions are demanded to circumvent the potential influence of the yet high CO2 emissions on the climate. In general, the total CO2 emissions can be controlled by reducing the energy intensity, limiting the carbon intensity, or by im‐ proving the CO2 sequestration. In the short term, carbon-based fossil fuels will persist to be the main source of energy. Thus, there is an urgent need to develop economically feasible and efficient processes for capturing, separating, storing, sequestering, and utilizing the con‐ tinuous CO2 emissions. The future trends, however, should be directed to reduce energy consumption and dependence on fossil fuels and to develop large-scale renewable and less carbon-intensive sources of energy, such as nuclear energy (e.g., H2), biofuels, geothermal,

lieved to cause drastic changes such as global warming and ocean acidification.

