【Pioneer of HaiChuan Chemical】Liu Ruozhuang – The founder of computational chemistry in China

According to a obituary issued by Beijing Normal University, Liu Ruozhuang, an academician of the Chinese Academy of Sciences and professor at the university’s School of Chemistry, passed away in Beijing at 0:35 on October 8 due to illness that proved untreatable, at the age of 95. The farewell ceremony for the deceased is scheduled to be held at 9 a.m. on October 12 in the Bamboo Hall of the Babaoshan Funeral Home in Beijing, with a simple funeral service.

On May 25, 1925, Liu Ruozhuang was born into a clerk’s family in Beijing. In 1943, he entered the Department of Chemistry at Furen University and completed his studies thanks to the scholarships he received each year. After graduating from university in 1947, he went on to pursue graduate studies at Peking University, shifting from organic chemistry to physical chemistry. On the eve of his graduation in 1950, he was retained at the university as a lecturer due to his outstanding performance. In 1952, following restructuring of the academic departments, he joined the Department of Chemistry at Beijing Normal University, where he was promoted to associate professor four years later.

In the 1950s, theoretical chemistry in New China can be said to have started from scratch. The renowned chemist Tang Aoqing returned to China to teach at the Department of Chemistry at Peking University, where he began to teach courses related to structural chemistry; Liu Ruozhuang served as his teaching assistant. From 1963 to 1965, Tang Aoqing held academic seminars on material structure at Jilin University. Liu Ruozhuang participated as one of the 8 official trainees and conducted in-depth research on the methods of coordination field theory, making significant contributions to the development of this field; his research achievements later won him the **First Prize in Natural Sciences in 1982.

After the reform and opening up, Liu Ruozhuang creatively applied quantum chemistry theories and computational methods to study reaction pathways and kinetic issues along those pathways, achieving a level that is at the international forefront. According to the Chinese Academy of Sciences, his main achievements include proposing theoretically a new view that substituents can alter the nature of the interaction energy between reactants and influence the reaction mechanism in addition reactions ； The isomerization reaction predicted the existence of certain unstable isomers, which was later confirmed experimentally ； It reveals the origins of the negative activation energy in radical reactions, among other things.

In 1978, Liu Ruozhuang established the Quantum Chemistry Research Laboratory at Beijing Normal University, which later became an important hub in China for using quantum chemistry methods to study real chemical systems, as well as a key outlet for theoretical chemistry in China to engage with the international community. In 1981, he was approved by the State Council as one of the first supervisors for doctoral students. He also taught graduate students in the Quantum Chemistry Research Laboratory, delivering courses on core subjects such as quantum chemistry, constantly updating his teaching methods. Liu Ruozhuang once wrote in a memoir: \"In my classes, I pay close attention to their grasp of the fundamental skills in their field; I believe these are the abilities on which they can rely throughout their lives.\" ”All his hard work indeed paid off; one of his first graduate students in quantum chemistry, Jian Guo, later became the lead expert in the Theoretical Chemistry Innovation Team at Beijing Normal University, and he still believes that the foundation he built back then was what gave him the strength to succeed. Among the other students, many also became renowned scholars in the field of quantum chemistry both domestically and internationally.

In addition to teaching students at his own university, Liu Ruozhuang also organized several short-term training courses. For example, starting in 1984, he led training programs for teaching assistants in material structure, aimed at providing further education in quantum chemistry for such teachers and domestic visiting scholars, thus making positive and significant contributions to the development of related disciplines in China. Fang Weihai, an academician of the Chinese Academy of Sciences, was once a participant in that training course and remembers having attended Liu Ruozhuang’s lectures from start to finish. “The content was actually quite difficult at the time, but thanks to Mr. Liu’s clear explanations and his ability to present complex ideas in simple terms, I was able to understand everything.” ” After Liu Ruozhuang’s passing, Beijing Normal University issued a obituary stating that he had pursued academic work with rigor throughout his life, was brave in exploration, loved teaching and cared for his students, encouraged younger scholars, and remained indifferent to fame and wealth. “His academic integrity and noble spirit are worth learning from forever.” ”

In the autumn of 1947 (the 36th year of the Republic of China era), Liu Ruozhuang graduated from the Department of Chemistry at Furen University, and was admitted as a graduate student in the Department of Chemistry at Peking University with excellent grades. During that time, he first studied organic chemistry under Professor Yuan Hanqing, researching hydrogen bond systems through experimental methods; this experience laid the foundation for his subsequent interest in hydrogen bonds and, ultimately, in the theoretical aspects of organic chemistry. Later, he moved under Professor Sun Cheng’e to begin research in physical chemistry. In 1949, he published his first research paper in English in the Journal of the Chinese Chemical Society titled \"Modified Troutons Rule\".

In March 1950, Liu Ruozhuang, who had not taken his graduation thesis defense, was allowed to remain at Peking University as a teacher ahead of schedule due to his diligence, eagerness to learn, and excellent academic performance. While teaching organic chemistry and quantitative analysis experiments, I began translating the English version of \"Fundamentals of Theoretical Qualitative Analysis\". In June 1950, Liu Ruozhuang successfully passed his graduate thesis defense with the paper titled \"Calculation of Specific Heat Using Mechanical Integration Methods\". His graduate thesis was published in the same year’s Acta Chimica Sinica. While working as an assistant in physical chemistry, he began to engage in research on quantum chemistry under the guidance of Professor Tang Aoqing.