Pauline

Linus Carl Pauling

Linus Carl Pauling is a famous American chemist and one of the pioneers of quantum chemistry and structural biology. In 1954, he won the Nobel Prize in Chemistry for his work on chemical bonds, and in 1962, he won the Nobel Peace Prize for his action against the ground test of nuclear bombs.

Character experience

The road to success

Pauline was born in Portland, Oregon, on February 28, 1901. He was smart and studious when he was young. At the age of 11, he met the psychology professor jevries. Jevries had a private laboratory. He had done many interesting chemical demonstration experiments for young Pauline, which made Pauline have a love for chemistry since childhood. This love made him embark on the road of studying chemistry.

When he was in middle school, he did well in all subjects, especially in chemistry. He often immerses himself in doing chemical experiments in the laboratory and aspires to be a chemist. In 1917, Pauline was admitted to the Department of chemical engineering of Oregon Agricultural College (now Oregon State University) with excellent results. He hoped to realize his ideal by studying university chemistry. Pauline's family situation is very bad, his father is just an ordinary pharmacist, his mother is sick. The family's income is low and living conditions are poor. In the face of financial difficulties, paulin suspended from University for one year to earn his own tuition. After returning to school, he relied on work study program to maintain his study and life. He once served as an experimenter of analytical chemistry teacher, and also served as an experimental class of grade one in the fourth grade.

Pauline studied hard under difficult conditions. He was very interested in the theory of chemical bonds, and at the same time, he seriously studied many subjects, such as atomic physics, mathematics, biology and so on. These knowledge laid a solid foundation for paulin's future research work. In 1922, Pauline graduated from university with excellent results. At the same time, he was admitted as a graduate student of California Institute of technology. His tutor was the famous chemist Noyce. Noyce is good at physical chemistry and analytical chemistry. He is very knowledgeable. He was kind to the students, and the students evaluated him as "very good at encouraging students to love chemistry".

Noyce told Pauling not only to stay in the book knowledge, should pay attention to independent thinking, at the same time to study the physical knowledge related to chemistry. In 1923, Noyce wrote a new book called principles of chemistry. Before the book was officially published, he asked Pauline to do all the exercises in the book during a holiday. It took Pauling a holiday to finish all the exercises accurately. Noyce was very satisfied with Pauling's homework. Noyce appreciated Pauling very much and introduced him to many famous chemists, which made him enter into the social environment of academic circles very quickly. This is very useful for paulin's future development. Under the guidance of Noyce, Pauling's first scientific research project was to determine the crystal structure of Molybdenite (mosz). Pauling determined a large number of data with the method of modulated X-ray diffraction, and finally determined the structure of mosz. This work has been completed very well, which not only makes him show his talent in the chemical field, but also enhances his confidence in scientific research.

Paulin was introduced by his tutors at Caltech, and he also got the careful guidance of Dickinson and torman. Dickinson was proficient in radiochemistry and crystalline chemistry, and torman was proficient in physical chemistry. With the careful guidance of these tutors, paulin further broadened his knowledge and established a reasonable knowledge structure. In 1925, Pauline got his Ph.D. in chemistry with outstanding achievements. He systematically studied the relationship among the composition, structure and properties of chemical substances, and also explored the relationship between determinism and randomness from the perspective of methodology. He believes that people's in-depth understanding of the structure of matter will contribute to people's comprehensive understanding of chemical movement.

After receiving his doctorate, Pauline went to Europe in February 1926 and worked in the sovieffei Laboratory for one year. Then he worked in Bohr Laboratory for half a year, Schrodinger machine and Debye laboratory. These academic researches made paulin have a profound understanding of quantum mechanics and strengthened his confidence in solving chemical bond problems by quantum mechanics. From his postgraduate study to his study tour in Europe, he met the world's first-class experts and directly faced the cutting-edge problems of science, which was very important for his later academic achievements.

Chemical contribution

In 1927, Pauline returned to the United States after a two-year study tour in Europe. He served as an assistant professor of theoretical chemistry in Pasadena. In addition to quantum mechanics and its application in chemistry, he also taught crystal chemistry and offered academic lectures on the nature of chemical bonds. In 1930, Pauline went to Europe again to study ray technology in Prague laboratory. Later, he went to Munich to study electron diffraction technology. After returning home, he was employed as a professor by Caltech.

When exploring the chemical bond theory, Pauling encountered the problem of explaining the tetrahedral structure of methane. According to the traditional theory, there are unpaired electrons in the outer layer of atoms before the combination. If the spins of these unpaired electrons are antiparallel, they can form electron pairs and form covalent bonds between atoms. When one electron is paired with another, it cannot be paired with a third electron. When atoms combine with each other to synthesize molecules, it depends on the overlap of the outer orbitals of atoms. The more overlap, the more stable the covalent bond will be. This theory can not explain the tetrahedral structure of methane.

In order to explain the tetrahedral structure of methane. In 1928-1931, Pauling proposed the theory of hybrid orbitals. The theory is based on the fact that the motion of electrons is not only particle, but also wave. And waves can be superimposed. Therefore, paulin believes that when a carbon atom is bonded to four hydrogen atoms around it, the orbit used is not the original s orbit or P orbit, but the hybrid orbit formed by mixing and superposition of the two. The distribution of energy and direction of the hybrid orbit is symmetrical and balanced. The tetrahedral structure of methane is well explained by hybrid orbital theory.

In the structure theory of organic chemistry, paulin also put forward the famous "resonance theory". Resonance theory is intuitive and easy to understand, and it is easy to be accepted in chemistry teaching, so it is popular. Before the 1940s, this theory had an important impact, but by the 1960s, in the centralized countries represented by the Soviet Union, chemists' psychology was distorted and distorted, they did not know the freedom of science Why did he criticize resonance theory like a storm, and put paulin in the name of "idealism".

When he studied quantum chemistry and other chemical theories, he creatively put forward many new concepts. For example, covalent radius, metal radius, electronegativity scale and so on. The application of these concepts is of great significance to the development of modern chemistry and condensed matter physics. In 1932, Pauling predicted that inert gases could combine with other elements to form compounds. The outermost layer of inert gas atoms is filled with eight electrons, forming a stable electron layer, which can not be combined with other atoms according to the traditional theory. However, Pauling's quantum chemistry view that heavier inert gas atoms may form compounds with elements that are particularly receptive to electrons was confirmed in 1962.

In fact, he is one of the founders of molecular biology. He spent a lot of time studying biological macromolecules, especially the molecular structure of proteins. In the early 1940s, he began to study amino acids and polypeptide chains, and found that there may be two kinds of spirochetes in polypeptide chains, one is a-spirochete, the other is g-spirochete. After research, he further pointed out that: a helix is connected by hydrogen bonds to maintain its shape, that is, long peptide bond helix winding, because in the long chain of amino acids, some hydrogen atoms form hydrogen bonds. As an important form of protein secondary structure, a-spirochete has been confirmed by crystal diffraction pattern, which lays a theoretical foundation for protein spatial structure. These research results are the projects that paulin won the Nobel Prize in chemistry in 1954.

After 1954, paulin began to study the structure and function of the brain and put forward the molecular basis of anesthesia and psychosis. He believes that the understanding of the molecular basis of psychosis is conducive to the treatment of psychosis, thus bringing gospel to the patients with psychosis. Paulin was the first person to put forward the concept of "molecular disease". Through his research, he found that sickle cell anemia is a kind of molecular disease, including the metamorphosis of hemoglobin molecules determined by mutant genes. That is to say, if one of the amino acid molecules of hemoglobin is replaced by valine, it will lead to the deformation of hemoglobin molecules, resulting in sickle anemia. Paulin concluded that sickle cell anemia is a molecular disease. He also studied molecular medicine and wrote the paper "psychiatry of orthopedic molecules", pointing out that the research of molecular medicine is of decisive significance in solving the mystery of memory and consciousness. Pauling is knowledgeable and has a wide range of interests. He has studied a wide range of cutting-edge topics in natural science. He is engaged in the research of Paleontology and genetics, hoping that this kind of research can uncover the mystery of the origin of life. He put forward the idea of nuclear model in 1965, which has many unique features.

Call for peace

Paulin firmly opposes the use of scientific and technological achievements in war, especially nuclear war. "Science and peace," he said

Chinese PinYin : Bao Lin