query: Why was helium hydride ion HeH$^+$, not hydrogen H$_2$, the first molecule formed in the early universe?
positive_passages.docid: 156516
positive_passages.text: Was helium hydride really the first molecule?
negative_passages.docid: 143495
negative_passages.text: Are there published predictions that hydrogen could remain metallic at ambient pressure?
negative_passages.docid: 141632
negative_passages.text: Is the Higgs boson an elementary particle? If so, why does it decay?
negative_passages.docid: 55948
negative_passages.text: Negative energy levels in the diagram for a hydrogen atom
negative_passages.docid: 62883
negative_passages.text: Positrons versus holes as positive charge carriers
negative_passages.docid: 77905
negative_passages.text: Why does an atom remain uncharged after emission of an alpha particle?
negative_passages.docid: 112625
negative_passages.text: Reduced mass in quantum physics (Hydrogen Atom)
negative_passages.docid: 65422
negative_passages.text: How did Bohr come up with the figure $n\hbar$?
negative_passages.docid: 77229
negative_passages.text: Why is Helium-3 better than Deuterium for fusion energy production?
negative_passages.docid: 27213
negative_passages.text: Why does a helium filled balloon move forward in a car when the car is accelerating?
negative_passages.docid: 54548
negative_passages.text: Expectation value for $\frac{1}{r}$ in the $|nlm\rangle$ state of hydrogen
negative_passages.docid: 80540
negative_passages.text: Elements and their plasma state
negative_passages.docid: 52974
negative_passages.text: Why are the higher angular momentum states of a hydrogen atom closer to the nucleus?
negative_passages.docid: 55615
negative_passages.text: Can a single molecule have a state?
negative_passages.docid: 18026
negative_passages.text: How can it be that the beginning universe had a high temperature and a low entropy at the same time?
negative_passages.docid: 25262
negative_passages.text: Why can we apply the $E=hf$ equation for electrons?
negative_passages.docid: 122419
negative_passages.text: Why do we study Atomic and molecular physics as a separate part in physics and that also in a very very detailed manner ,when we have proved it wrong